10 June 2010

9mm QR or 10mm bolt through

This was fun. (Ok, I was bored in bed with a cold)

As it was raining and this is what I had been thinking about all morning, I went out to the garage, got my Vernier Callipers out and got measuring. Not something you think or talk about generally, but may be of interest to some people in my situation. Keep in mind that my Vernier Calliper is a cheap and nasty item so these measurements may be "slightly" off.

1. Rockshox Tora 289 disc fork had a perfect 9.00mm slot for axles on one side and 9.10 on the other. Oooh ! Probably paint and muck.

2. Steel MTB non-disc V brake fork had a 9.75mm slots for the 9mm QR axle supplied. Ahhhh ! (I must have done 1000 miles on this fork, often loaded like a donkey.) Looked OK.

3. Yuba Mundo V3 disc fork had a 10.10mm slot and a perfect 10mm on the other leg. Cooorr ! Probably paint again making for the difference.

4. My "standard" 9mm QR axle came in at 8,82mm in diameter... argh !

5. My original V2 Yuba Mundo front axle came in at 9.52mm diameter... ( I could see a slight gap between it and the drop out.) Looked OK.

My questions;

Is it Ok to run a standard 9mm QR in a 10.10ish slot with brake discs ? I get the feeling some people are going to do this without seeing an issue.

Or do I need a special 9,52mm axle disc hub up front ?

Looking at the numbers and fitted it looks really sloppy, it would probably work for a ride around the block, but discs do load axles, so I am faffing around on the internet trying to find somebody with THE knowledge. The Yuba is such a pick and mix of fun industry standards that it is quite unique and not always easy to follow on the best of days

My worry since I first popped a wheel in these forks is that the gap between the 9mm axle and the larger fork drop out slot edge would allow flex/axle movement/slip under load, over stress the skewer and/or make the brakes/forks judder. Or even lead to wheel loss.

I hope that this will be a simple general knowledge question, and that the cough medecine will wear off soon and my mind will clear.

I will probably learn that each manufacturer is slightly off the industry standard anyway depending on the day of the week or whats on the radio, that bike manufacturing is not aerospace manufacturing. But this is a bit off for me. I want to keep my teeth and avoid front wheel loss incidents...

Aren't home builds fun... there is always something that you don't know for sure... and this must be my 20th something bike build !

Opinions and knowledge welcome !


  1. I don't think it will matter for the front fork. Looking at my fork, where the nuts for the axle go is slightly countersunk. I think that is what they call 'lawyer lugs'. This would stop the axle coming out of the fork. I'm using Pitlock locking skewers. My Yuba build for touring http://meganleewebb.blogspot.com

  2. I have run a 9 mm QR in the Yuba fork ends, and my current fork is a 10 mm with a 9 mm QR disc hub in it running 185 mm hydraulic disc brakes on the Yuba. I haven't run into any problems with this beyond the usual disc brake set-up tweaking process and they have actually been pretty solid and reliable. I think Sheldon Brown ran some wheels in drop-outs they weren't meant for using the QR skewers compression only to hold the wheel in place, with no axle in the drop-out at all. Even if it isn't a completely perfect mating between hub and fork at first you can bet the softer Yuba steel will change shape a little over time to perfectly accommodate whatever hub you run in there.

    If in doubt you could always buy the Yuba wheel(s).

  3. Thought about this again this morning before reading your comments just now and I think you guys are right. As long as the axle is up in the crotch of the dropout and the skewers are done up to the right tightness it shouldn't move about, even if there is a gap infront and rear of the axle in the drop out slot. There are the lawyers lips too if things are done up too loose, so I think this was just a case of overworrying on my part.

  4. On a different topic, I see that Yuba's webstore has a "wheels4life" special edition Mundo. For $899 you get 2 Mundo's- one for you and one for Wheels4Life. Check it out and spread the word! John

  5. Jim, I am a Jim as well, great name!

    Your blog inspired me and I now only use the Yuba with a carseat as my main mode of transport. Panniers are confounding me though. I bought the large one from Yuba, but it doesn't fit very well with the car seat on as well. I noticed yours and really like them, but every set of panniers that i find has the little hook at the top and it never seems to fit over the wide tubing on the yubas built in rack. What brand of panniers are you using?

  6. Jim,

    I use Altura panniers, although a lot of other panniers use the same Rixen and Kaul fixings. There is a screw on the clips so you can increase the width of tubing they can accommodate (even the Yuba) I also have a vaude bag which has clips which can go on tubing as wide as 20 mm.

  7. Hi Jim, I have been off working on the otherside of the country and I am about two blog posts late !

    My panniers are last year's Decathlon model. From memory they were about 30 Euros. They are tough, well thought out, practical and can be carried around like a small suitcase using the strap handle. They fit like they were made for the Yuba and the top is flat so you can sit on them too. No hooks, bolts etc. Just scratch strips.

    Decathlon sports superstores are very common in Europe and even Britain. I even saw one in China I think !

    If you are some where far away they have a website store www.decathlon.com but I don't know if they deliver everywhere.

  8. I have a 9mm axle/QR in a 10mm fork slot with a disk brake. When the brake is applied, the wheel twists sideways (slightly) moving in the slot, which is a bit off-putting! Are there 9mm ID/10mm OD bushes available?