zxy007

After having replaced the brake cable and pads for my rear brake on my winter hybrid commuter (Fugi Sagres) I took my bike to a LBS to see if somebody there could tell me why my rear brake was not grabbing. For several months my rear brake has felt spongy, it worked but barely....as I said it felt spongy.

So, I went to a LBS thinking I would buy a new rear brake (linear side pull) when the bike mechanic who was attending me suggested we put the bike on a stand and see what was going on. He promptly agreed that something odd was going on but suggested that the problem could be fixed by a set of new brake pads and some tweaking...even after I told him the brake pads were barely two months old.

So I left the LBS for 30 minutes to find a coffee shop as the mechanic said he could work on the bike immediately. When I came back he told me that the actual problem was because the rear wheel had become out of true and had lost its "dish". I should add I had also recently replaced the rear wheel for one that had a quick release mechanism as I did not want, while winter commuting, to be forced to use a wrench to get a tire off to fix a flat.

I told the mechanic that I was surprised that the wheel needed to be trued and was out of dish as I had the receipt from December that showed that I had bought the wheel from the same LBS. I am getting ahead of myself...the mechanic said the reason that the brake was not grabbing was that the brake was only grabbing on one side because if I understand correctly one side of the wheel was closer to a brake pad than the other. I was skeptical at first because by habit I often visually check the wheels of my bike for signs of any wobble and had never seen anything that would cause me to check for loose spokes. However, as the mechanic spoke I checked the spokes and I could tell that some of them were not as stiff as they should be....blah, blah, blah....

Well, the rear brake is working but now I am wondering if what happened was an aberration, or if next winter should I plan to have my wheels trued every 45 days...More facts, ...I commute about 35 miles a day 7 days a week. I know winter is hard on a bike and I had been some what cavalier about spending much money on basic maintenance as I figured I would either have to toss the bike at the end of winter or give it a major tune up before parking it until next fall. It is my first winter commuting and so I don't know what is normal...I am pretty anal about making sure my wheels are trued but is it true that a wheel can appeared to be trued but be out of "dish"....is it normal for wheels to go out of true quicker during winter commuting and if so is there a way to minimize the issue...e.g. increasing spoke tension?

mulveyr 

Wheels do not go out of true because of winter commuting. Or summer, fall, or spring commuting, for that matter.

They go out of true because a) They've been damaged by falls or crashes, or b) They're crappy wheels. When my touring wheels can go thousands of miles while loaded over every possible sort of terrain without needing to be trued - ever - the "mechanic" is full of it.

Were these wheels built by the shop, or just sold off the shelf? Either way, they need to take care of the problem.

"is it true that a wheel can appeared to be trued but be out of "dish"

No. By definition, a trued wheel is centered in the frame, which requires correct dishing. You cannot have one without the other.

electrik

If the wheel was out of dish it was because you trued it yourself improperly or the dish wasn't originally checked by the mechanic who assembled the wheel.

It is also possible you did not lay the axle flat in the rear drops after changing a flat.

Closed Office

Wheels need truing when they go out of true, and as a couple people mentioned, the season has nothing to do with it. I don't follow the mechanic's logic at all. Even if the wheel is off center at some point the brakes will still grab both sides.

Makes me glad I fix my own stuff.

Sixty Fiver

I true my wheels once when I build them and then wait for the rims to wear out.

Off the peg wheels do not come with the same level of finish and it is common for them to de-tension.

zxy007

Hmmm, I did at the time think I was being hustle but after I noticed that a few of the spokes were borderline I thought I see what the mechanic could do...I normally do my own work, but I just could not figure out what was going on...Yes, I bought the wheel off the shelf from the same place...I did not examine the wheel too closely as the shop guarantees that their wheels are sold as being "trued"...I have never had a flat or had to dismount the wheel. I think from now on when I buy a wheel I will do a better job checking the spokes....I would like to learn more about the physics of tensioning and detensioning....Recently I heard on a Two-Johns podcast an interview of a person from Edge Components about carbon tires and he touched on the subject.


Thank you for your comments.