Bicycle TutorBicycle Tutor

Show off your bike!

Related video tutorials:
Tires don't fit
#1
Thank you in advance for any advice given. I am a newb to the cycling world. Last year I started commuting about 80 miles a week and I'm loving it. A few weeks ago I decided to switch out my tires to a narrower tire for reduced resistance. Let me just say that I am on the verge of defeat and I need advice. I am very capable physically and I am quite mechanically inclined. I have removed and re-mounted the stock tires multiple times using Park Tire Levers to check and re-true my wheels.
I will try to explain what's happening to the best of my ability. I'm sure I will get some nomenclature wrong so please be patient with me. I'm also sure that some of you will want to advise me to buy a real bike or buy expensive components. I bought the best I could afford and that will not change as I buy components. I am a commuter but I push myself hard to make the best time possible. Please give advice accordingly. My bike is a Diamondback Maravista 2007 model. I bought it new in 2008. The rims are Weinmann AC-19 700c x 19c rims. Actually, here's a link for all the bike info:
http://www.bikepedia.com/Quickbike/BikeSpecs.aspx?Year=2007&Brand=Diamondback&Model=Maravista&Type=bike
The stock tires are 40c. I want to go down to 28c tires. The first set of new tires I tried were Serfas Seca Road Tires in 700c x 28c. After spending two weeks and a lot of knuckle tissue trying to solve this major problem, I figured there may be something wrong with the tires so I bought a different set. Now I have Vittoria Randonneur Cross Tires in 700c x 28c. The problem remains the same. The only other factor I can think of is my tubes. I switched those out to a thick thorn resistant tube of appropriate size. With no more delay, here's the problem.
Mounting the tires was nearly impossible. I even powdered the tires to make it easier. Getting them back off several times during this process has been so bad I've nearly decided to cut them off; but I haven't. After mounting the tires, and inflating the tubes, there is a very noticeable flat spot, about eight inches long, along the circumference of the tire. At this flat area, the tire bead simply does not reach the outer edge of the rim. By 'outer edge' I mean where the tire bead is supposed to seat as you inflate the tube.
I have inflated the tubes to as high as 140 p.s.i. in an attempt to force the tires to expand to the bead set. Within this eight inch area, the tire twists to one side or the other since it is not expanded against the rim at its greatest circumference. I can actually twist the tire by hand to straighten it, but it moves back as I continue to manipulate the tire.
My belief is that these rims are manufactured incorrectly. I believe their diameter and, therefore, circumference is too large. By the way, the stock tires did not have this problem. They were 700c x 40c Kenda Cross tires.
Please help if you can as I really need to get back on the road. It's been three weeks and I'm getting the shakes.

Reply
#2
There is variation in the precise dimensions of various rims. So I doubt they were manufactured "wrong" per se. But you are right that the shape/size of the rim is not matching up to the tire well. Thinner, higher pressure tires are generally made to fit tighter than larger 'cross' tires.
I suspect the heavy duty tubes will actually make the tires harder to get on and off. But I don't think it would affect the tire not seating correctly.
In the past I've put something a little slippery like windex on the rim where the tire won't pop out and put them at full pressure. Usually they will pop out and seat right after a little while. But if that doesn't work, I think you may be back to trying different tires again.
The unfortunate fact is that rim and tire manufacturers all make their stuff slightly different sizes. You will find one brand of tire is looser than another. You might find that folding tires are better than wire bead, but they are generally more expensive. Ask your local shop if they have experience with the tires they sell. They may be able to recommend ones that are generally "looser" on the rim. Or maybe someone out there has a good recommendation. Maybe even bring a wheel with you in to the shop and try a tire while the sales guy watches.

Reply
#3
Right, I don't recognize the rims you have but I can guess that if you started with 40c tyres they are quite wide. This is probably where the problem lies. The tyres will fit properly though, I guarantee it. What you want to do is get a thinner set of tubes 700x 23, ok. Get the tyres on as best you can. To eliminate the flat spot mix fairy liquid with water and pour it all over the uninflated tyre where it meets the rim, right. No water will stay in the tyre as it will be forced out when you pump up the tyre. As you pump it up a pop should be audible as the bead snaps onto the rim. If done properly this will work every time.

Reply
#4
Thanks so much for the advice. I'll try it again tonight and I'll let you all know how it goes. Thank you again.

Reply
#5
It worked just like you said it would. A little lubricant goes a looooooong way. Thank you again for your advice.

Reply
#6
pleasure

Reply
#7
Sorry to bring up an old thread - but had exactly the same problem as akakj5, and spent lots of time trying in vain to force the bead into place on a new tyre / rim combo

Finally, went to look for advice on this site and used chainbrain's dish detergent solution. Worked like a charm! Thanks.

I love this forum.
Reply
#8
The only drawback I can foresee is if you have a puncture and try changing the tube out on the road.
Will the tyre re-fit without the lubrication?
[font=Trebuchet MS]Ride hard or ride home alone![/font]
Reply
#9
I suppose I'll need to carry some liquid soap with me at all times on the bike!

Seriously, I don't think I could get the tyres back on out on the road. Too tight. Don't know if that's a problem with all Vittoria's, but I had a hell of a time just getting them on the rims.
Reply
#10
I have fitted hundreds of tyres in my time in the bike trade and have rarely had these problems and almost never had to resort to lubing the tyre, your tyre and rim combo are very common and should not produce this problem and I suspect there is some other cause.

Have you checked your rim tape, its not uncommon to find the tape is too wide and rides up on one side and prevents the tyre seating properly, if so, trim it down or fit a narrower tape that lies completely within the narrowest width of the rim.

you may also want to read this,
http://www.schwalbe.co.uk/shopdata/files/TechInfo2-GB.pdf
especially page 6 "Which tire fits which rim?" and page 15 "Why do wide tires roll better than narrow ones" although its too late now!
Reply
#11
trevgbb - thanks for the link, that doc is quite helpful. Most of it I knew already more or less, but the info about wide tyres rolling better than narrow ones is new to me and quite interesting.

Anyway, my tyre / rim combination, Vittoria Diamond Pro 23-622 and Shimano Ultegra 6700 Wheels (622x15C 700C) normally should work fine, but I had an absolute nightmare of a time putting on the back tyre. Partially destroyed 2 plastic tyre levers, and really bloodied my hands. The front tyre was also a minor struggle but managed it with a little help from a tyre lever. I have no rim tape on these particular rims because they are compatible with clinchers or tubeless, there are no spoke holes, and the Shimano SI doc specifically intructs not to use rim tape.

I haven't changed as many tyres as you, but I have done a few, and have never had such trouble before. Without the levers it would have been completely impossible, especially out on the road.

Do you know any other tricks / hints for tight tyres?

Thanks
Reply


Forum Jump:



ISSN 1918-3445 © Copyright 2007-2010 Bicycle Tutor / Privacy Policy / Created by Alex Ramon

feed