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-   -   Flat repair (https://www.bikeforums.net/bicycle-mechanics/899745-flat-repair.html)

road1bike 07-05-13 03:33 PM

Flat repair
 
I ride a Giant Escape City and got a thorn in my rear tire today.

Took it to REI for the repair, and added some liners.

I got home and realized the tire was rubbing the brake pad when I spin it.

1. Should the bike shop true the wheel as a par tof the flat repair?
2. What tires would you recommend for better flat protection.

HillRider 07-05-13 03:54 PM

1. The shop shouldn't be expected to true your wheel during a flat repair unless you request, and pay for, that service.
2. Learn to change a flat tire. Even the most "bulletproof" tires will sometimes get a flat.

cny-bikeman 07-05-13 03:56 PM

It's not the tire rubbing the brake pad but the rim (outer circular metal part of the wheel). Truing a wheel (fixing a small area or areas that hit the pad) is a separate job from flat repair, but the shop should have pointed out the out of true condition, and offered to fix it either at the time or by you leaving the bike. If the rim rubs the pad all or most of the way around it's not truing that is the problem but incorrect installation of the wheel, which is definitely the shop's error.

It's always a good idea to look over the bike and if possible ride it before leaving the vicinity of the shop. If you don't want to fix your own flats that is fine, but I highly recommend that you have someone show you how to do a routine "quick check" of your bike. You can also Google "bicycle quick check" - there's at least on video available.

FBinNY 07-05-13 04:32 PM

As others have said, being able to fix a flat is just about mandatory for anyone who rides more than a few miles from home. It's easy and many bike shops, including most REI stores offer courses from time to time.

Aligning a wheel isn't part of fixing a flat, but if the wheel wasn't rubbing before, odds are it didn't suddenly get that way. The shop probably failed to check the exact wheel position when installing it (with horizontal dropouts). If you have vertical dropouts the shop might have not pocketed the wheel fully into the dropouts (a common error among mechanics who install wheels with the bike elevated) or bumped the brakes, or with canti's moved the yoke carrier which moves the brakes over.

It's also possible that the prior mechanic didn't pocket the wheel correctly, and set the brakes to match the wheel position, so when the wheel was correctly seated it rubbed.

Either way, if the wheel didn't rub before, and is aligned decently enough to clear the brakes (up to 2-3mm wobble) then it is the mechanic job to restore it to the non-rubbing condition. This isn't a wheel alignment, just a proper install. BTW- as any pro mechanic will tell you, they'll often correctly install the wheel and find the brakes now rub. This is a fact of life, and all that I know will do a quick brake adjust for free because they have to rather than return a bike in non-working condition.

road1bike 07-05-13 04:39 PM

The rim hits the brake pad at a certain point on every revolution. If I had been made aware of the problem I would gladly have paid to have it repaired. Now I have to go back.

I will look into learning to repair my own flats.

Any advise on tire upgrades.

Thanks for your help!!!

jowilson 07-05-13 04:47 PM


Originally Posted by FBinNY (Post 15818691)
Aligning a wheel isn't part of fixing a flat, but if the wheel wasn't rubbing before, odds are it didn't suddenly get that way. The shop probably failed to check the exact wheel position when installing it (with horizontal dropouts). If you have vertical dropouts the shop might have not pocketed the wheel fully into the dropouts (a common error among mechanics who install wheels with the bike elevated) or bumped the brakes, or with canti's moved the yoke carrier which moves the brakes over.

+1. I always check the wheel alignment in the dropout after I take my bike off the stand. Most of the time it isn't centered.

cny-bikeman 07-05-13 05:11 PM


Originally Posted by road1bike (Post 15818703)
The rim hits the brake pad at a certain point on every revolution. If I had been made aware of the problem I would gladly have paid to have it repaired.

Indeed, it's in both your interest and the shop's to fully inform you. It's not acceptable to put out a bike that's rubbing on the rim.


Originally Posted by road1bike (Post 15818703)
Any advise on tire upgrades.

If you are having flats from road hazard punctures (as in the thorn) I have had good experience with Kevlar belted tires. "Pinch flats" occur when tires are underinflated or too small for conditions. It's important to know what caused the flat to know how to avoid future ones. The cause of a flat is also something a shop should ideally convey to the customer.

road1bike 07-05-13 06:14 PM

Took it to my LBS and he adjusted the brake. I offered him $10, he took $8. Maybe I'd better become my own mechanic.

Thanks again.

redbuda 07-05-13 08:56 PM


Originally Posted by road1bike (Post 15818977)
Took it to my LBS and he adjusted the brake. I offered him $10, he took $8. Maybe I'd better become my own mechanic.

Thanks again.

You'll save a lot bread. Check to see if there's a bike coop kitchen in your area. They also teach basic repairs and will help you and teach you to work on it.

cny-bikeman 07-06-13 07:42 AM


Originally Posted by road1bike (Post 15818977)
Took it to my LBS and he adjusted the brake. I offered him $10, he took $8. Maybe I'd better become my own mechanic.

Thanks again.

So you saved $2 on the wrong solution - adjusting the brake to avoid rubbing on an out-of-true wheel.

FBinNY 07-06-13 09:11 AM


Originally Posted by cny-bikeman (Post 15820307)
So you saved $2 on the wrong solution - adjusting the brake to avoid rubbing on an out-of-true wheel.

We don't know how far out of true the wheel was. It might have been true to within 1mm TIR but simply positioned wrong, or positioned right but the brakes not. The fact that a brake adjustment solved the problem seems to indicate that the wheel is basically OK. Of course the mechanic might simply have opened them up to clear the out of true wheel.

My point is that there's not enough info to render an opinion, and we have to defer to the mechanic who actually saw the bike.

cny-bikeman 07-06-13 09:18 AM

OK, point taken, though I hesitate to defer to the judgment of a mechanic who left the brake rubbing in the first place.

kenji666 07-06-13 09:25 AM

Learn to do your own simple repairs, and you'll not only save money, but also time, which can be used for more riding!

FBinNY 07-06-13 09:38 AM


Originally Posted by cny-bikeman (Post 15820560)
OK, point taken, though I hesitate to defer to the judgment of a mechanic who left the brake rubbing in the first place.

We agree there, and I wonder if the brake adjust was something he should have done (free) when remounting the wheel, or if he did something more comprehensive. We also don't know if the wheel was properly set when the brakes were adjusted or whether the OP will have a repeat problem next time.

When I visit shops, I often see mechanics install wheels while the bike is in the stand, and many of these will cheat the cheat to center the brakes when doing repairs. By eyeball estimate, less than one out of five pro mechanics will put the bike on the floor to properly set the wheels before centering the brakes. That doesn't mean that 4 out of five do it wrong, because many achieve the same end by neutrally pulling the wheel up into the dropouts --- but many don't.

cny-bikeman 07-06-13 10:58 AM


Originally Posted by FBinNY (Post 15820634)
When I visit shops, I often see mechanics install wheels while the bike is in the stand, and many of these will cheat the cheat to center the brakes when doing repairs...many achieve the same end by neutrally pulling the wheel up into the dropouts --- but many don't.

Agreed - the standard at the Bike Co-op where I was Quality Control Agent (not sure why we did not call it Service Manager) was to finish the wheel mount on the floor, spin the wheels and "bounce test." It's amazing how many small overlooked things one can discover just by lifting a bike a couple inches and bouncing it on the floor. Loose headsets, rattly reflectors, loose fixing bolts for racks, etc.


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