Box Components have corrected the mistakes they did with the first generation on Box One rear derailleur, the parts are now Forged aluminium, not Cast, so it’s much more durable. But I saw the angle and position of the B bolt is still not optimal, it half way out of the hanger, but so far this has not been an issue, but with previous generation I had issues on my old bike it are through the hanger, so I had to reverse the bolt, but this has not happen with this bike, at least not yet, but I will see if it does. this review is just a quick review, but in long term review I will report back.
How firm it was set, It might have been too firm for me to use with mechanical shifter, but it can easily be adjusted so that would not be a problem, but for me ergonomics for shifter might be an issue, I haven’t tried Box One shifter, but from looking at videos, pictures it does not seem like it would fit me well. I used Shimano XTR M9000 before, which did not fit me at all, but it performed well and was durable, but I sold it. but now I use Archer D1X , so it’s doing the heavy lifting instead of my thumb.
The bushings can be replaced, by taking the Rd apart, so in theory you could run it for decades, if you replaced the bushings.
With 50T I had to turn the B-bolt all the way in which you can see in the picture below.
looked at the clutch and adjustment, this system looks like a good solution. I tested the #tripackclutch clutch adjustment, so far this is the best clutch solution I have seen, very easy to adjust, just take the cover off, and adjust the 3mm hex bolt. Taking the clutch out is easy too, just pull it by the bolt,then you have access to the 4mm bolt securing the cage. I also tested the cage spring the cage spring has similar feel to Shimano, I can easily move the cage with one finger if clutch is adjusted to minimum.
A look at the clutch:
Here you can see the cover from the side with a O-ring sealing it.
I like that seal is an O ring , so that should be easy to get replacement for. not a proprietary seal like Shimano has.
The thing you see in similar shape of a flower, is in two parts, so if dissembling be sure to align them correctly to be able to put it back in the rear derailleur. These parts are just to keep it in place.
I saw Sram’s Cage Lock is nice, but it’s not really needed, in this video I show how easy it is to remove wheel without using a Cage Lock, which is a feature Box One does not have.
after the initial review back in 2018 , I have updated the review, some improvements, and added videos.
I have used it for few months.
I haven’t had a very hard impact on the bash guard yet, but I had one light scrub, which barely gave a mark, but once I get a big impact I will update you on this.
The bash guard is mounted with two Torx screws to into the plate, which makes assembly and disassembly is very easy & fast, there is no need for two Torx screws like with MRP AMGv2, but the only bad thing about this is if you ruin the threads, you cna’t just swap bolts, but it keeps the weight down.
Doesn’t clog up with mud, 77designs designed a great chain guide, it does the job well, without any unnecessary bulk or material, mud will travel through the big hole.
easy to take the chain off, due to the simple and great design of the guide, you just undo the bolt little bit and swing the front guide, with Loctite 243 and proper torque it will stay on securely.
the chain guide from 77 Designz seems to be good, with keeping the chain in place, I tested how well the chain will stay on by forcing it off the chainring, the plastic pushed it back on, so I think the chain will be very secure on the trail no matter how fast or hard you ride. I think it does a better job than MRP AMG v2, which is not really made for oval chainrings.
Broken Bash plate
First I used 34T oval, which the guide supported but for this chainring size the bash guard could be few millimetres longer, to protect against very uneven stone edges, but I later switched to 32T Oval and that should not be an issue for sure, I have also ordered new bash guide plate, the size was 28-32T which was exactly the same as the original.
I intentionally did stupid things to try to make it drop. I forced the bike when the chain got stuck in a tree stump. this video shows what happens if you do, I of course would not do this mistake otherwise, just lift the bike way from it make sure chain is in place, and everything is fine then ride down. I think you can drop the chain with any chain guide, if you are brutal enough.
I did the things in the video to test it, the guide did not fail, but chain dropped, which I suspected would happen. I’ve not had the chain drop with this chain guide otherwise. also it does not get clogged up with mud.
I will update you on further developments.
More pictures of the guide mounted on my Nicolai/Geometron G1
Going from Xt m8000 with uncut 116 link Kmc x11 Sl silver chain, I had to add 5 links, due to the bigger tension pulley, but with 34T Oval I could use stock chain length. But if I were to use 32T or smaller I don’t Think it would be an issue, but I haven’t tested this.
It’s easier to clean the jockey wheels than on Shimano rear derailleurs, due to the more open design, the jockey wheels are more exposed & the lower is bigger.
But the Top pulley is also more exposed, and easier to clean than on Shimano.
The cage swings very smoothly
You can fully take it apart, as the swing arms have E clips, so removing them is easy with a screwdriver, So far Box does not offer every single part as a replacement.
I have had the chance to smash it, on this technical section this was the result : so far it seems to be ok, can handle some scrapes.
The rd moves easiest up from the the highest gear/smallest cog, at the second smallest cog it the resistance can be felt, it gets worse and worse the bigger the cog.
I noticed there was a difference in how stiff the springs were between the two Box One rd’s I got, one still has a stiff spring.
I prefer Shimano trigger shifter, So I use the XTR m9000, it seemed like a good combo, but the stiff spring is way too fatiguing.
The shifting is very smooth, it’s actually smoother than Shimano XT M8000, because of the cam clutch, it gets stiffer as the lower gear you use, but this makes the high gear as there is no clutch at all, this is probably also due to the initial movement where the clutch does not seem to engage, but this won’t be an issue unless you ride like a madman within the top gear, so any issues are unlikely, But I read reviews saying they dropped the chain, but some of them did not use chain guides.
The shifting is very smooth, similar to Shimano XT M8000, but in higher gear as I mentioned before there is more play in the cage before the clutch actuate, but on Xt it’s much more efficient clutch,m which can be adjusted.
It gets stiffer as the lower gear you use, but this but in the smaller cog if feels lighter, due to less resistance. But this won’t happen with normal riding, so any issues are unlikely, But I read reviews saying they dropped the chain, but some of them did not use chain guides. I guess the chain could drop if back-pedalling downhill in max gear, which no one normally does, or even on the flat you will feel the chain slap. I rode pretty hard and fast in technical sections and I never had any issues, but eventually it was a problem, when the bushings wore out there was so much play that it created more slack in the chain probably causing the chain suck i got On my fuel ex, But this happen before too, but that was due to the cassette being worn I think, but maybe it already started back then summer 2018, but that issue was gone when I swapped back to the XT cassette so it probably was not, but the issue came back after using the Xt cassette for a while, but the cassette was significantly more worn, and the Box One Rd has a lot more slack and sag, The initial play of the clutch is also a contributor I think, and both combined were causing problems, but just the slack chain alone would be causing issues, when shifting it had issues both ways so I think it was march when I swapped back to the XT rear dérailleur, and later I swapped back to Sun Race cassette, which I will run until I get a new Rd, I think it will be the next Box One.
In this video you can see how the bushing wear is on a Rd used month, few weeks, few days.
You can see the chain is slacker, and the Rd is sagging, I did not dare to use the Rd with the bolt the right way because I was afraid of ruining it, so I did what I did on the Fuel Ex, but this does not allow me to adjust the B bolt for the wear in the bushings to remove the slack, so I would have to do that or shorten the chain.
Fitted on the bike with Uncut KMC 11x Sl silver chain:
The Box One Rear dérailleur has a harder spring, which increases the fatigue I get from shifting, which already was pretty bad Shimano XT M8000 rear dérailleur
The clutch was quite harsh/ stiff in the start, but it eventually wore down, so the gets weaker than the Xt M8000 clutch can be.
I noticed the downshifts were smoother with the Box one, but this might be do to the worn clutch and heavier spring. The lack of adjustment is a big flaw, but this is resolved with the new generation of Box One, it has completely new internally adjustable clutch.But I haven’t found out if the spring has gotten lighter on the new generation, but it won’t matter anyway if I get Archer components DX1 electronic shifting system, which I think I will need, because I fatigue my hands by shifting.
The Spring tension is so strong is actually abusing my thumb significantly more than the XT M8000 RD would, to the point in the tip of my thumb like a needle, if I do too much shifting, it can take days before my thumb is back to normal.
Last time it took 10 days before the pain was gone, also I had to use a lot of hand cream, the skin was wearing off at the tip of my thumb at faster rate in the winter and spring, due to dryer skin, of course having hand cream helps, but I forgot to apply it before riding, but I have been doing since that day again, but there is no cure for the pain I get when riding for 4 hours and shifting a lot, the rides after this ride I had to minimize my shifting to bare minimum, to avoid pain, only shifted when absolutely necessary, but if riding in a place that requires a lot of shifting, like I do at & to Skansehytta in Askim, and ride for 4 hours it’s I will get pain for sure, but then rest of my body will be tired too, if I ride fast or do a lot of technical stuff, but it’s always the thumb that fatigues first, even with rides I do less with my whole body as long as I have to shift a lot I get pain, so it can happen on even shorter rides.
So mechanical trigger shifter especially with activated clutch on the rear derailleur is not great for me, to abusive, especially with so strong spring tension, even with days or weeks of using hand cream and my skin is being normal, after several hours, my skin gets some wear, and pain, on not as long rides, but for the longer rides I get a longer lasting and more painful experience, but with XT RD it was much it happens at a much slower rate, and not as painful.
The Clutch is not adjustable, so when it wears you can’t regain hte same performance, But the new version has adjustable clutch.
The B Screw & threads in the body for B screw failed, it’s most likely due to alloy used, the next version comes with Forged alloy parts, so it should be more robust, it’s promising.
At first glance, I thought I had to adjust the B screw, But a few seconds later noticed that the screw has chewed off the edge of the hanger. Since then, I fully unscrewed it I discovered the threads were ruined, But then I discovered the B screw was switching between light and hard to turn as I unscrewed it, this was caused by the threads in hte body being completely destroyed. So I put Xt M8000 on the bike.
Rhis Rd is not really compatible with Trek rear dérailleur hangers, I haven’t tested it on other brands.
I hope the new Box One Rd will be strong enough for the threads to not fail, Also I hope other hangers on other bikes I want won’t have a shape that cases the bolt to not sit properly against it, the Trek hangers sure don’t work with this RD, but does with Shimano And Sram, I don’t know if the New RD has changed the position or angle of the bolt
The position of the B screw does not help, I am quite sure it’s the reason the hanger got so damaged, but maybe the hanger on my bike should be thicker where the B screw is, but I think the B screw position is not optimal, and the combination of the placement & not using forged alloy resulted in failure. but using the rear dérailleur with upside down B screw with nuts for extra support, seems to work well, I haven’t had the issue on the other Rd. for Shimano Xt 11-46T I used one nut, for Sun Race 11-46T I used two nuts.
Dislocating cam clutch spring, the spring wears out and becomes too big, and creeps out on both sides of the O ring until most of it pops out.
I don’t know why, but the bolt got loose, so I cleaned it and put Loctite 243 and it held on.
Some pics of the RD that did not fail:
The threads did not fail on this Rd, I know the body is not strong enough as I have seen failures by other users on Instagram, this one did not have any issues yet, but I reversed the B bolt and added nuts from reflectors for support, it has not failed the few weeks I used it a lot.
There is definitely potential, Box has some great ideas, for example, use of bushings, but there some flaw that can’t be ignored.
BOX one has great potential, but the current rear dérailleur should not have been released to the public, as the product has major flaws, I hope these issues are fixed in the new generation of Box One.
So I can’t recommend the First generation of Box one Rd at this stage, but I can’t really recommend any other mechanical rear dérailleur or shifter either, I really hope they will fix this issue, by offering a free rear body upgrade, which would be easy to do, & easy for the more custom to install, as the Box ONE Rd can be fully disassembled, with only a screwdriver & Allen keys.I recommend keeping up to date with Box is doing..
Since 6 months review in Jan 31 2018, I have taken a lot of pictures, I have improved this review a lot, but I might update it again.
later may 21 2019 I added videos and improved the text.
The barrel adjuster is nice easy to adjust the wire tension.
A look inside:
A closer look at the mechanism:
The back plate is made of plastic and is secured with tree thicker bolts and a tiny screw.
Here you can see the top of the mechanism, the hexagon keeps the shifter to rotate, the bolt goes through the hole. the white stuff you see is the original Factory grease.
A closer look at the mount:
The carbon down shift lever got scratched, but it was fine:
I have managed to scrape up the Carbon trigger, I don’t know how or when, but probably in one of the few crashes I had, probably on asphalt or rock, but it held up well without any cracks or other damage, even after a year after this scratch happen.
Removal of bottom cover requires moving it over the lever, be careful doing this so you don’t damage the cover
Triggers withstood winter use
The shifter triggers withstand winter use,the downshift lever is made of carbon, The up shift trigger seems to be made of plastic carbon mix. Unlike some other plastic triggers shimano had to offer in the past, these don’t fail after few months of winter use,same goes for the xt version, but xt version has alloy downshift lever, and plastic trigger, but it can withstand winter use.
Where I live winter can be as – 10c midwinter, January, February, also a lot of temperature changes up and down, and very varied temps and conditions on the start and end, but they withstood it all very well, zero cracks.
No position adjustment:
Currently there does not seem to be a trigger shifter on the market that fits me, and have all the adjustments to make it fit me. also the fatigue I get from shifting makes Electronic systems interesting like Archer Components: https://www.archercomponents.com/
I have have tried the latest Sram shifters in my local sporting goods store, they too were not made for my hands, but at least they got a adjustment to the downshift trigger, to adjust the angle, but that’s not enough, but just by looking at it I could tell it would not work for me, also I can tell the other shifters I have seen won’t work well for me. I haven’t had the chance to try the latest 12 speed Shimano shifter yet, but I can see from reviews on YouTube and pictures on in the magazines, it does not seem like they would fit me well.
Shifters has to have adjustments to make it fit big and small hands and all in between, having one size does not work well. this has bothered me for many years, but most things with contact points on bikes has been fixed, some even like they read my mind, but I am sure I am not the only one who wished for many of these things.
The thumb will rub against the lock on clamp when shifting with the XTR M9000 shifter, but this is not the Grips’s fault, I would like some more adjustment for the XTR shifters, but so far this has not been an issue yet, this of course leads to wear where the thumb rubs.
here you can see thumb at the down-shift lever.
Another thing is when using the up-shift trigger with my index finger, I have to move my finger in uncomfortable way, I have to reach for the trigger or move my hand to actuate the trigger, but when using my thumb it will rub, but if I place it where it would be natural to place it, it sits half way on the trigger.
But as this is a shifter it’s not wearing as fast as a rear derailleur would, so it will last for ears, not much play has developed, if any, but I also have serviced it several times, to keep it running smoothly.
The lack of adjustment makes it impossible to set up properly even if this shifter fits you, with some brake s it might not work good.
With the new Shimano brakes(M7000, M8000, M9000), there is more room for clamping position.
XTR Shifter & TRP Spyke lever is not a good combo, with the Spyke lever I have less room to play with shifter placement.
This shifter does not fit me:
I would like to change the position of the shifter, for a better fit but the XTR M9000 shifter does not allow me to do this by default, I haven’t looked at alternative mounting solutions much, but the times I looked I did not find anything.
With my thumb joint issue causing the thumb to misaligned sure does not help when shifting, the big movements and pressure from the spring tension is fatiguing on it’s own, but the issues I have can cause even more problems, also make it more painful to shift when it happens, and having a Shifter that does not fit me, creates even more fatigue.
The shifter also has a firm click, it’s significantly different, from other Shimano shifters from the past, so you can feel the actuation better, but this adds to the fatigue I guess. But not as much as a rear derailleur with a clutch too tight, for example the first gen Box One ,which is actually abusing my thumb, to the point in the tip of my thumb like a needle, if I do too much shifting, it can take days before my thumb is back to normal.
Both triggers have play, the play has been present in all Shimano shifters I have used or tried.
The clamp is well engineered, for lightweight, but the connection between the mount & the shifter is flawed, there is slight rotational play between the mount and the shifter.
I have used it the XTR m9000 shifter with the Box One first generation rear derailleur, but the spring is a lot firmer than the spring on Shimano XT M8000 rear derailleur, so this makes it harder to downshift, more fatiguing, but even with the Shimano XT M8000 rear derailleur shifting is quite fatiguing, but that’s the negative part of a mechanical shifting rear derailleur.
Issues with bolts getting damaged too easily:
I have experienced too soft bolts on several drivetrain components, shifters, rear derailleurs, So this was not a surprise.
The bolt holding the shifter to the clamp was not tight enough when I checked it, so I unscrewed it applied Loctite 243 and screwed it back in, the bolt got damaged some, the stronger bolt should have been used, this is disappointing, but the bolt is supposed to be titanium, but there is too much wiggle room, which results in damage, even with a hex hey or bit that has great tolerances, it still will be bad, I have experienced this problem with several bolts from shimano, they all suffered from this, but not all have gotten as damaged yet, but they probably will eventually, you should insert tool and turn and not have wiggle room, but I can move the hex bit or key in evry direction, this is not something most people aspect from a high-end component, But I do, sadly there I see too many shortcuts in the bike industry.
I have tested several positions, and none of them worked well for me. but I settled on this one, but it will not be perfect.
For better grip I installed Tesa Anti Slip tape, on all controls, including the shifter, this has gave a much more secure shifting experience. of course there are other options, I just got this tape from one of my local hardware stores.
The difference in feel between XT & XTR:
Shimano XTR Shifting XT M8000 RD
First things I noticed compared to the Xt m8000 was the different feel, which is difficult to explain, but it’s different.
Shimano please make mounts and other components compatible with cheaper shifters, for example, the clamps, covers, and so on.
as you can see that xt clamp is overbuilt, unless they use different type of material, that requires it, though the rest of the shifter is not.
but it would be nice if there was just on shifter with several versions instead of the making it different just to be different and not compatible.
I could not compare & test the durability & longevity of the cassettes in a accurate & scientific way, but here is my experience with it so far. I have been swapping between 3 wheel sets, and various time of use, only way to accurately test it is a machine with exact same abuse.
The cogs eventually bent/twisted, but it took much longer than on the XT casette,
the Sun Race Cassette is more flexible, but also more resistant to ”permanent” bends.
I have 3 wheel sets I rotate, when one needs a service or something is wrong I can just swap, so I haven’t used the cassettes 100% equally amount of time.
I am not sure if the flex in the FuelEx’s that did this or if its the cassette’s fault.
it was more resistant to blends but is more flexible than XT cassette.
I have of course regurally chainged the chain when it got to 0.40mm stretch. and lube the chain well, an done every htign correctly.
The Last ride on the last cassette:
I worn out 2 of the tree cassettes, and June 2018 I worn out the last one.
The cassette was so messed up, that the chain dropped to the smallest cog.
I knew the cassette was going to wear out soon, and it did,the chain dropped to the smallest cog. The hanger was bent too.
the smaller cogs are have bent teeth & twisted teeth, some of the cogs are bent too.
there is no way I can twist the teeth back to be straight with any tool I got. if it was just the cogs a screw driver would probably do the trick, it did before on several XT cassettes.
I had to put on Xt cassette I had.
The Sun Race cassette was more resistant to the abuse The Fuel EX frame set put s the drive train trough, but eventually it got abused too much.
Back on the Sun Race cassette
The backpedalling issue was gone when I went from 34t to 32t oval chainring.
I could pedal backwards without the chain dropping or skipping or any high noises.
The range seems to be what I was looking for.
With 11-46T x 34T oval I found I needed a smaller chainring, so I got 33t. I could have gone for bigger cassette, but I did not need the high gear the 34t offered. And I will stick with sun race 11-46, as Shimano xt m8000 does not offer the a good transition to the largest cog.
I have been through several cassettes and put it through its paces.
Due to the design of the cogs, the transition from each cog is excellent. The chain stays well in place with unrealistic fast backpedalling, where the sun race cassettes would drop the chain, my bike has hope pro 4hub, Absolute Black 34t.oval chainring, this but the chain at an optimal angle for the biggest cog, so this clearly shows the sun race cassette performs worse with backpedalling. As mentioned in many other reviews, the jump to the 46t cog is too big, it messes up your cadence, but I got used to it.
The XT cassette has quite stiff cogs when the chainstay wore out on my 2014 fuel ex the extra side to side movement combined with bearing misalignment caused the cogs to bend, but this will not be an issue on a bike that does not have an extreme side to side movement or bearing misalignment issues. So, in conclusion, the cassette performed well.
This part seems to be made of some sort of plastic composite.
The wire clamp is a weak point, not only because the plate bends, but if the threads fail, due to a hard impact or whatever reason, you need a new rear dérailleur. The wire plate bent to the point of the wire slipping, but I managed to bend it back on a bike path, but I flipped it, and used it for several months without issues, But I ordered Spare anyway.
I replaced the seal, as it lost some of the elasticity & stiffness, the bolts holding the cover in place held up well.
I changed the whole clutch assembly, not only the axle, I noticed the original spring lost the stiffness, the new one was a lot stiffer.
The scratches you see on pull arm is was caused by the chain grinding on it, it was when I had Bontrager Duster 29 on the bike, which was not good for 11 speed as the cassette was further in than the Hope Pro 4 Enduro wheel, Hope Pro 4 hubs are 11 speed compatible freehub, which places the cassette further outwards giving you better chain line & eliminating back pedalling chain drops. Even though there are some scrapes I have not had a hard crash with it yet. Time will tell how it will hold up, But I will not use it as much as it will go on the trek 6300, which I only use as a spare, But so far there has not been any significant damage from the small spills.
The clamping plate eventually bent after few months, eventually the wire slipped, and I I had get it straightened enough to be usable, and then I put it back with the wear to the top, eventually the plate was straighter, but I eventually installed new plate just in case, to me it seems like the wire is bending the plate after long little by little, it seems like a flawed design. also the nut bolt trough plate design is no longer in use as on previous XT so the threads are in swing arm not in a nut.
Fully assembled, seal for cover for the clutch replaced, wire clamping plate, the seal hood for the clutch adjustment, which also eventually wore out like the original, hopeless, it wears out fast, and eventually falls off.
here you can see the new plate installed
Better jockey wheels installed..
Did the 2014 Trek fuel ex 7 damaged the RD? or was it faulty?
The axle failed & the chain got bent, So first I tried warranty, but that did not work, but later, I became quite sure it was my frame that caused it. The Rd still had some life in it, So I ordered spares from SJS Cycles, but Shimano Norway would not warranty it as there was another damage, which actually is just cosmetic damage.
I am quite sure now the reason cage axle failed, was it due to major flex in the 2014 Fuel ex 7 frame under pedalling load? or was it faulty cage axle? I Don’t know.
no use of bearings or bushings, causing shorter lifetime, which is a compromise.
not well optimized for wide range cassettes, So the use of goat link or similar is necessary, but if doing so, it performs very well.
plastic jockey wheels which wear a lot faster than metal
The clutch lever is plastic and is flimsy, it bends.
the bolts are quite fragile, the head damages easily, the tolerances between the tool and the bolt is not great, there is a wiggle room, causing the bolt to wear, even with most accurate tools out there it won’t solve the issue as the bolt head it self is the issue, but having it will definitely help, it’s the case for all of the bolts.
Plastic clutch switch is flexy and fragile it seems, I have seen pictures online of it snapped, impacting it might snap it, I haven’t done it, I don’t smash Rds often, if I do any damage it’s just scratching.
good shifting performance, if the clutch is well adjusted, by having a hard clutch you get harder lever action, so optimising it for you is important, I can’t have it super hard, the shifting performance is good with the Xt m8000 cassette, but also with the SunRace cassette, but the Sunrace cassette, has back-pedalling issues So I can’t recommend it.
very easy to service the clutch.
2019 update: the spring is not as strong as on Box One first gen, which was so strong it was fatiguing me even more than the XT M8000.
I will use the Xt Rd for a while, to not fatigue my thumb as much with Box One but I think I will switch from mechanical shifter to Archer D1X electronic system to get less fatigued, because even with the lighter spring on XT M8000 it still can be too much for longer rides.
Even trough the guide itself is made of plastic, it held up well.
I have been riding pretty fast in rough terrain, up and down steep trails, jumped, did some stunts, and drops, riding down steep stairs(40-50 degrees)in low gears, the chain never came off, there were not many signs of wear, but eventually you will have to change the guide,(the plastic part with Mrp logo), but I have been using it over a year and held up well, not much wear.
one of my first thought about the guard was it might get much mud stuck in it, but even though I have been riding in bad weather, there were not much dirt or mud stuck in there. But as long as you don’t ride in extreme condition, with a lot of mud, in something like Danny Hart’s 2011 world cup run, or even thicker mud, I am sure It won’t be an issue.
I there was some missing spacers, and I lost some of the thin spacers,but later I found them, so I switched to 2x thin spacers, which should, be better, but I still think bigger gravel can get stuck in between the chain ring and chain guide, but this is impossible to avoid.
But Now as I have a Sortimo boxes I don’t have a mess so it won’t loose any more small parts.
Make sure you Use the right spacers.
After riding a lot in the spring I noticed scrape on the 36T cinch narrow wide race face chainring, which I think is caused by a stone getting stuck between the chainring and the chain guide, causing a perfect circle scrape.
I had the bike in the repair stand, after riding on gravel paths, I noticed that there was a stone stuck in the chain guide and was scraping the chainring, and fell down again, I think that’s what happen the last time.
Very easy to install, & setup, No need to remove crankset or chainring to install the chain guide,
Minimalistic design, no bulky or unnecessary big parts.
after few hits, no damage done
all of the guides I got had missing thick spacers, and missing short screws.
Mrp claims it should fit 38 T chainring, But in my opinion, 36T is the max, with 38T the plastic will be too close to the edge of the chain. so if the guard was few millimetres bigger, it would fix 38T better, but I don’t need a 38T ring anyway.
Not properly Oval compatible:
Although MRP list this guide as Oval compatible it does not work as well with oval, due to the ovality of the chainring, the narrowest point of the oval causes more room and the chain could squeeze trough between the ring and guide.