HELP: on tour, need disc brake advice
 

My wife and I are currently in the middle of a multi-year world cycle tour: http://www.goingslowly.com/

Our Velocity rims failed in Switzerland a few months ago:
http://journal.goingslowly.com/2009/...city-rims.html
http://journal.goingslowly.com/2009/...rs-arrive.html

Velocity was great and replaced our entire wheelsets for free.

We're now experiencing the same failure on my wife's rear rim.

Velocity is willing to send us ANOTHER wheelset but this time around we need to switch to disc brakes. We need cable operated disc brakes that will mount to a pair of Surly LHTs with Tubus Tara and Tubus Cargo racks. My wife has trekking bars, I have drops. I'm not sure if our existing brake levers will work?

Our complete gearlist down to the brakepads is here:
http://www.goingslowly.com/gear/

Any advice you guys can give would be greatly appreciated. I've never dealt with disc brakes but I need to figure out what we need and soon. Hopefully Velocity will be willing to send us the brakes with the wheels if we send some money because we're on a desert island off the coast of Tunisia right now.

Thanks!

ugh, it looks like our LHTs don't have the required braze-ons.

As you already noted, LHT frames and forks don't have disc tabs, so mounting a disc system on there is not going to be possible without some sort of adapter (which are rare but do exist, but are not really recommended).

My first question is why do you need to switch to discs though? Is the replacement rim going to be disc only? That seems strange because Velocity makes a ton of rim-brake compatible rims.

The more I look into this the more I remember the research I did before we left. We're definitely not going to go with disc brakes. The issue is that we've now had 3 different Velocity rims fail in less than 10,000km. Velocity has been great and eager to support us by sending free replacements but I'm concerned that we're just going to wind up with another failure in 3 months if we don't change something.

Another solution would be to try a different rim manufacturer entirely but given our location and Velocity's willingness to help us it seems way too complicated/expensive to do that.

That is one of the big advantages of having disc brakes on a touring bike. Because of the heavy loads, rims wear out much quicker from braking when you are touring, especially if you're touring the rain and going down a lot of steep grades.

That said, I had a long discussion about putting disc brakes on an LHT with a guy at the local bike shop. He firmly advised me not to put them on the front without replacing the fork, as he thought the LHT fork would not due well with the stress of discs. He also believed that there would not be enough space between the seat stay and the chain stay for a caliper to mount properly, even if you had someone braze on the attachment, so you would have to mount the caliper on top of the seat stay, where it would interfere with racks.

Compare the seat stay design of a disc-specific Salsa Fargo (made by the same people who make the LHT) to the seat stay design of the LHT - compare also the fork design and the strength of the fork design:

http://www.salsacycles.com/images/zoom_fargo_fm.jpg

http://www.surlybikes.com/uploads/frames/FM6760.jpg

Anyway, I think you've got four options, in order of expense and difficulty:

1) Keep blowing up wheels and (hopefully) getting free replacements
2) Get stronger, heavier wheels that last longer
3) Get a different frame designed for disc brakes, as well as disc hubs, rotors, brakes, and wheels
4) Get a new fork for your LHT and have someone braze disc mounts on the frame somehow

If it were me, I'd go with option (2)

Out of curiosity, what rim did you start with, and what did Velocity replace it with (that you're having trouble with now)? Are your Long Haul Truckers 26 or 700c versions?

According to the blog, they were using the Cliffhanger rims initially, but I can't see those listed on Velocity's website under 700C size. The replacement wheels use Chukka rims. The original post here says that the replacement wheel is now starting to fail, which sounds really odd - only a few months of use doesn't sound right - and I can't see any mention of the latest failure on the blog, just the original one back in September. Could the OP perhaps give some more details on what's going on with the replacement wheelset? Is it failing at the join, or in some other way?

This is particularly interesting to me since I am in the process of ordering a Co-Motion Americano, and they use Velocity Dyad rims. I was going to go with rim brakes on this bike, since as far as I can tell from extensive reading of forums posts on the topic of rim vs disk, it seems that rim brakes should be fine for most touring applications. But this is making me think twice... I know it's one data point, but it does make you think. What do others here think about Velocity rims for touring? Apparently the ones that failed here are pinned rather than welded. I don't know offhand if the Dyads are welded.

See following:

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You are now using stronger rims. I think the problem you are experiencing is pretty unusual. If there is no research that indicates that the new rims (or the old ones, for that matter) or the manufacturer give other people problems, there might not be any real issue. That is, it may be very unlikely that you'll have the same problems again.

It's possible that there was bad run of rims (which could explain why your 3 rims failed: ie, they where made at about the same time). The fact that you are using different rims, made at different times, should eliminate this as an issue.

Their website indicates that they are using 26 inch wheels. The original post is confusing. It does seem to imply that they are having the same problems with the replacement "chukker" rims. If this problem is characteristic, one would think that it would be easy to find other similar stories. (Peter White, for example, would have likely heard of any problems and discontinued using the rims.)

They seem to be saying that the whole wheelset was replaced, and one of the new wheels is failing again already.

I wonder if this is partially a maintenance issue with grit embedded in the brake pads causing excessive wear. The picture of the "hairline crack" at the seam doesn't indicate anything to me, that's the seam. I'd suggest an entirely different rear wheel for one of you and see if there's a difference over the next year. Sun Rhyno?

When my Cliffhanger failed in Switzerland I checked my wife's rim to discover hers had the same cracks near the rim joint. Journal entry on the day of the faliure here: http://journal.goingslowly.com/2009/...ulierpass.html

Velocity replaced all four wheels with Chukkers, front and back just to be sure we wouldn't have issues. The 40h Chukkers w/ machined sidewalls were from a small run. They don't stock them for sale.

Our front rims have had no problems, the Cliffhangers we're fine too but Velocity wanted to make sure we didn't have rims from a bad batch.

My wife's NEW rear rim (the replacement Chukker) is now failing with the same weird looking crack. The braking surface around the crack is bowed out but this time the crack isn't near the rim joint. The wheel can be ridden but the rear brakes had to be removed to make room for the bulge.

Also, it is definitely not a maintenance issue. I am anal retentive about our brakes and rims now. We've been running koolstop salmons for our entire trip specifically to avoid this sort of thing.

Thats honestly really weird. The Chukker is basically a beefed up Deep V, which is itself a pretty durable rim... I'd imagine a 40h chukker is plenty strong to handle touring loads! All 3 that failed were rear rims, right? That seems to indicate that its not a wear issue (as the front generally wears faster than the rear). How worn is the rim?

What does Velocity have to say about it? Honestly, my first response is that you got really unlucky with some bum rims. That seems like a very unusual problem.

wow, as wonderful as Velocity has been maybe it's time for something completely different for the rear wheels? Are you at all adverse to simply getting a heavy rear wheel with 36 spokes with the option of commonly available heavy rims that Rigida or other manufacturers make for mtn. bikes? You can't beat lots of metal for heavy use. Sun rhynolite? Enjoying your website.

I've put a lot of loaded miles on Fusions with cantis with no problems, Neil.
I have Cliffhangers on my Big Dummy, but with disc brakes.

I mentioned this to a wheelbuilder I know, and he had this to say:

"Both the brake track wear and the separated pin joint on the blogger's site are sure signs of an overinflated large tire, in my opinion. When you use tires that are significantly wider than the rim, the tire puts an enormous lateral stress against the rim, visibly pushing the sides outward, causing premature brake track wear. It's common to overinflate the larger tires when touring when you're accustomed to using smaller tires that require higher pressure."

I have no idea if this is really what's going on, but it does seem to make sense, and it might explain why the new wheels are starting to fail in the same way. You might want to look at the tires (i.e. how big/wide are they in relation to the rims, all rims have a recommended range of tire widths) and also the pressure.

Neil

ah, the other shoe drops?

I am DEFINITELY willing to run a ridiculously heavy wheel. I do not care about speed in any way shape or form. Getting the wheel built and here in a timely fashion is the problem. I think I'm going to give Velocity one last shot and if we have more failures we'll go that route.

We run 60psi and the Cliffhanger was a pretty wide rim. I don't think that was the issue.

Velocity has been incredible. They were immediately willing to replace our broken rims last time with no questions asked. 4 brand new wheels shipped for free overseas in short order. I doubt we'd see service like that from any other manufacturer. They are equally willing to help this time around. I think we're just going to get one more rear wheelbuild from them and hope we just somehow ended up with 3 randomly bad rims. I have to say that my faith in Velocity's product is a little shaken but their customer service is second to none.

This ^^^

Makes total sense. You are using a 2" wide tire on a rim that is less than 1" wide (or 1.1" for your old wheels). Overinflation is also common given all the gear people carry touring. Time for wider rims or skinnier tires.

I'll pass this along to Velocity and see what they have to say. When they originally sent our replacement Chukkers I did confirm with them they'd be able to run our 2.00 x Marathon XRs and they said it wouldn't be an issue.

Most of the wheelbuilders using Velocity for touring wheels seem to use Dyads. Do you know why Volocity didn't send you those rather than the Chukkers? Did you discuss the different options at all?

I didn't really discuss the issues with them, no. I was shocked they were willing to send 4 new wheels for free and didn't really raise any questions beyond confirming they would be fine with our tires. I'm still waiting to hear back with what they are going to send as replacements this time around.

Kazer, is your pressure gauge accurate?