Tech Tip: A Simple Cassette Modification That Could Save Your Rear Wheel

by Steve Wentz

Every year there's a new race schedule, new parts, new bikes… lots of cool stuff to drool over.  I'm lucky enough to be able to go to some races, ride my bike and have good times with friends. One of the things that I definitely DON'T like is having to do is unnecessary maintenance on my bike. I like that my suspension is awesome, my frames are strong, and my brakes slow me down when I get scared so I can just focus on riding. However, rocks, stumps, and my own mistakes can and have made my back wheels go out of whack from time to time. A wobbly wheel and loose spokes in turn can cause far worse problems, especially with a downhill bike.

Tech Tip: A Simple Cassette Modification That Could Save Your Rear Wheel

This tip is particularly effective for downhill bikes, but four-cross, slopestyle, dirt jump, freeride and even enduro bikes can benefit from it as well.

We've probably all had a wheel eat up a derailleur that goes too far over into the spokes - it literally sucks. This is the last sort of thing I want to ruin a ride or race. To alleviate this potential fun ender, I've been doing the following modification to my bikes over the past few years with great success. I hope this may be able to help some other riders as well.

This is usually free, simple, and not that hard to do. But, I've also got to say that SRAM does not condone this. The cassette was designed to be run with all 10 gears (or 9, depending on the model) and this technically voids the warranty. However, I speed sometimes in my car and I'm not supposed to do that either.

Tech Tip: A Simple Cassette Modification That Could Save Your Rear Wheel

Here is how close a normal cassette setup gets to the spokes on a rear wheel.
 Not much room. This is the same for 9 speed or 10 speed, SRAM or Shimano. Everything butts up against the end of the freehub, which is very close to the spokes.

For this trick to work, you'll need to use a cassette that comes in multiple pieces. 

I like using the SRAM PG-1070 cassette because it has some individual gears down low that I can sort through and take out if needed.

Here is what the modified cassette looks like. In this case, I've taken out the 13 tooth cog on the cassette, which allows the rest of the cassette to be shifted over, away from the spoke. Note that there is considerably more room between the derailleur and wheel.

I like the 11-25 spread for DH racing, and now the cassette goes from the 14 tooth cog to the 12, then 11. If I happen to be motivated enough to pedal at 30 mph, that last thing I am thinking of is "am I on the 12 or 13 tooth cog in the rear?" Because my mind is usually concerned with not beefing it, I've never noticed a gear gone from my spread. I replace that lost cog width with a spacer between the 25 tooth cog and the wheel. This makes more space just in case the wheel gets out of whack, I hit something, or who knows what happens in a DH race.

With that extra room, make sure you adjust the limit screws on your derailleur so that the chain won't pop back between the spokes and the cassette. If it does (this happened to me once when I didn't adjust the limit screws correctly) I was able to just shift to a harder gear and the chain came right out without getting jammed.

Be sure to check the limit adjustment a few times, both with the chain off (easiest) and then with the chain on to double check.

Look at all that room! There is now more clearance between the spokes and derailleur. If the wheel gets out of whack or if you happen to smash the derailleur into a rock on accident, it's much less likely to get caught in the wheel and wreak more havoc. As an added benefit, this trick also provides you with a straighter chain line in all the gears you're likely to pedal hardest in.

I hope this trick will help us all keep the mechanicals to a minimum. I went through all last year with a couple of rims and few sets of brake pads. Not bad in the scheme of things. With a few small tweaks to your ride, you can be in the same boat too.


Have a quick tech tip that'll help save a ride from unnecessary mechanicals?
Spread the love and share the knowledge in the comments.

C50_twitter3_1382472127 bturman 11/25/2012 8:15 AM

24 comments newest first

I've gotten the same result with cutting the largest cog off a 28-11 cassette... gets similar gear range and the added clearance.
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great tip. i have struggled getting the chainline straight with my guide on. moving the cassette like this would be the perfect fix. never occurred to me to try this.
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One technique I've been using for a while is to put the cassette on backwards, so that the cogs closest to my spokes are the smallest anyway, preventing that big, nasty drop into the spokes if you over shift. Problem solved! Plus, to my understanding this does not void the SRAM warranty.
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chris.leoleis
Nick_Murdick
Ol Dirty Jose G
Did you also mount your derailleur on the inside of your hanger, or did you just disassemble it and reverse the parallelogram shifting action? There's no way that worked, especially with the ramped teeth and shifting pins on the cassette.
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Kurtdefreitas
This is a good tip!

The point of the tip is not to keep the chain or upper derailleur pulley out of the spokes, as some of the comments would lead you to believe. This is valuable for the lower pulley and cage of your derailleur interacting with the spokes when either your derailleur or wheel gets out of sorts.

When the going gets tough, the tough get going.
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SpokeApparel
right. had my derailleur pulled through my spokes twice. trashed the wheels both times that way,
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I heard Steve Wentz was really slow... And how does he even reach his handle bars? Why Listen to slow people like him anyways. No Thanks.
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TEAMROBOT
erik saunders
Hate to say it guys, but pretty bad advice. If you already are having to limit the deraileur limits to account for the spacer, why not just limit it properly so you don't shift into the spokes. Or if you want to keep it that much further, just limit out your lowest gear- a gear your much less likely to use on a DH bike than the 11 tooth. Adjust it properly or take it to a shop who can.

That being said, thanks for providing everyone in the shop today a good laugh.
I'm not going to get into an argument on the internet with you. I have 10 years of bike shop experience and have competed in down hill since I was a junior. Do this technique if you'd like thats your right. I personally will just adjust my limits as designed, align my deraileur hanger with the tool and will continue to do so on my customers bikes.

And maybe a guy as fast as swentz can get away with not running that highest gear (I've tried chasing him before and know he doesn't need it) But for the rest of us mortals its nice to be able to pedal the open sections. Especially given the trend in bike to get lower and lower, requiring smaller and smaller front rings.
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The problems I've had have been from the derailleur going for a ride with the spokes, not from the chain dropping inside the spokes, although that happened once without damage luckily. I just wish my hanger would have broke so I didn't have to replace the derailleur.
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I don't really understand what difference that would make since i usually use only the 3 fastest gears for downhill...
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Or, because it's a downhill bike, you can ditch all the unnecessary gears, and pull off the last 3 gears on an 9sp 11-32 SLX cassette. This gives you an 11-21 6sd cassette. All the gears you'd ever need, without having to double shift because all your transitions are so tight, and your chain won't ever get close to that rear wheel. And if you are a slopestyle/dj/park rider, you can shift into this empty space and use it as a freecoaster. (Aaron Chase did something close to this back in the day)

PS: It also helps if you build your wheel the right way. Drive-side trailing spokes heads in. The makes it so that the trailing spokes wont drive the chain down further into the freewheel during rotation, but instead push it up. One, this is the way Chris King requires wheels to be built around their hubs, and second, this will also make lacing your wheels easier. When you get to putting in the last 16 spokes (if you use the "Sheldon Brown Method"), because you push the spoke from the inside out, you don't have to weave the spoke in between all the spokes to get your cross.
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esstinkay
CR-
Hyperpower!
Uncle Cliffy
Daniel_Layton
That tip about the driveside trailing spokes laced with heads in is, IMO, a better tip than the one in the post. Although i like it too, i just wonder how much of a difference it really makes towards avoiding getting your derailleur sucked up in your spokes. I mean, if you have your limit screws adjusted properly then you won't have the problem of derailleur suck via an upshift anyway, and if some stump drives the derailleur towards the spokes, then how much will the 1 or 2 mm of extra spacing really do? Guess it depends on the average (or more precicely the distribution curve) of deflection of a derailleur by an impact but that would be difficult to quantify. This tip certainly can't hurt though
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I dont get it, just adjust your derail properly and you wont have an issue. Taking 1 cog out and moving the whole cassette over aint gonna help it from jumping into the wheel. Unless you only ride in 1st all the time...
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esstinkay
Ol Dirty Jose G
Uncle Cliffy
I once landed from a mellow jump and my derailleur got sucked into the wheel, snapping the derailleur into six pieces, breaking the shifter cable, snapping 6 spokes, bent up the chain AND snapped the derailleur hanger. It was a mess
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Or you could put that little plastic disk (that came on the bike) back in. You can find it at the back of the shop in a box with the reflectors. Still, a good idea you have.
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mbl77
PaucH
That plastic disc will stop the chain from eating into your spokes if it goes too far over, but it isn't going to stop a rear derailleur that is hit on a rock. The plastic disc is rendered useless by a well-tuned derailleur stopping the chain from coming over and does nothing in the way of a bent hanger.
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PHRANQUY
seei.fernandez
Spencer... I agreee, i just lock out my largest gear with my XO... and cuz the shifting into it shit anyways haha. so its a guard now
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PaucH
It seems to me that doing so creates a gap for the chain to get caught in and fold causing catastrophic failure. Wouldn't a better solution, (and one that doesn't piss off SRAM) be to just use the limit screw and... limit the derailleur stroke?
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esstinkay
OldSkoolAK
PHRANQUY