Author Topic: How to know tire size  (Read 6362 times)

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Offline Nyimbo

How to know tire size
« on: February 15, 2017, 02:23:16 pm »
My Vitorria Randonneur touring tires have 3000miles on them now. I think I would like to start my summer trip with new tires even though I'm sure I could do a rotation and get more out of the ones on thernow.  My bike is the REI Navara Randonee.

The bike came with 700x32. (BTW I'd like any answer but as well  I'd love  to know how to determine the answer for future knowledge sake) what size tires can I put on the wheels.

If I want to add some bike trails (such as the Katy Trail) on my route this summer a wider tire might be of some benefit for comfort.

Randonee:  http://www.adventurecycling.org/default/assets/resources/201202_RoadTest_Pelkey.pdf



indyfabz

  • Guest
Re: How to know tire size
« Reply #1 on: February 15, 2017, 02:44:28 pm »
For the A319 (Not sure what the S signifies. Maybe silver since it appears that the 36h comes in silver, not black?), Mavic recommends 28-47c:

https://shop.mavic.com/en-us/a-319-j24500.html

Offline Pat Lamb

Re: How to know tire size
« Reply #2 on: February 15, 2017, 04:40:46 pm »
The absolutely best way to figure out what size tire fits in a given frame is to try successively larger tires until you find one that doesn't fit.  Then back off a size or two because not all models that say 35 on the side are the same size.  (They should be, but in the real world, well ...)

I've ridden my 2009 Randonee with up to 37 Panaracers, and there was still room for more.  If there haven't been any recent floods, a 35 width tire should be plenty cushy for a crushed gravel trail like the Katy.

Offline RussSeaton

Re: How to know tire size
« Reply #3 on: February 15, 2017, 06:23:57 pm »
You have 700C by 32mm tires on the bike now.  Get some calipers and measure the width of the tire inflated.  Just to see if it is close to 32mm.  And get a tape measure and put it down by the bottom bracket and measure how much room you have on either side of the tire.  That will give you an idea if 35 or 38 tires will fit.  But as stated, the only sure way to know is to buy some tires and mount them on the bike.  Then look at the chainstays to see if they clear.

Offline DaveB

Re: How to know tire size
« Reply #4 on: February 15, 2017, 10:30:06 pm »
The wheels are probably not what will limit tire size.  The fork and frame clearance will be the determiners.

Offline RonK

How to know tire size
« Reply #5 on: February 16, 2017, 02:24:58 am »
It's not quite so simple as measuring the side clearance at the chain stays.

Tires will not only be wider, they will also be taller, so it is important to also measure the clearance from the top of the tire to the chain stay bridge, brake bridge and fork.

One of my bikes has plenty of side clearance at the chain stays but barely enough clearance at the bridge and none when a fender screw is in situ.
« Last Edit: February 16, 2017, 02:27:42 am by RonK »
Cycle touring blog and tour journals: whispering wheels...

Offline dkoloko

Re: How to know tire size
« Reply #6 on: February 16, 2017, 12:15:47 pm »
My Vitorria Randonneur touring tires have 3000miles on them now. I think I would like to start my summer trip with new tires even though I'm sure I could do a rotation and get more out of the ones on thernow.

Rotation: Rear wears 3x front. If you put worn rear on front you risk crashing in blowout.

Offline canalligators

Re: How to know tire size
« Reply #7 on: February 16, 2017, 02:38:49 pm »
Rotation: Rear wears 3x front. If you put worn rear on front you risk crashing in blowout.

Rear wearing that much faster is not my experience.  Maybe 50% faster.  And I'm over 200#.

Like on a car, rotating tires should be a preventative action, not a corrective one.  Don't rotate because your rear is worn out, rotate earlier to prevent the rear from wearing out sooner.  Tire rotation is an economic strategy, not a safety strategy.

That said, I don't put much credence in bike tire rotation. If you inspect your tires regularly, and replace when the tire is unsafe to use, you have done what you can to prevent a blowout.  Tire failures usually happen because they're damaged by road hazards or the cord starts to fail (it develops side-side distortion).

Offline Nyimbo

Re: How to know tire size
« Reply #8 on: February 16, 2017, 03:48:35 pm »
 I'm guessing that my experiences similar to most others. On my road bike and my hybrid my tires have always worn fairly close to evenly.  On my touring bike riding with loaded panniers I found my rear wheel is much more worn.

 Sorry my math is not that good I'm not sure how to convert 3X and 50%  to each other. :-)

Offline dkoloko

Re: How to know tire size
« Reply #9 on: February 16, 2017, 04:24:21 pm »
I'm guessing that my experiences similar to most others. On my road bike and my hybrid my tires have always worn fairly close to evenly.  On my touring bike riding with loaded panniers I found my rear wheel is much more worn.

 Sorry my math is not that good I'm not sure how to convert 3X and 50%  to each other. :-)

Certainly not my experience. Quote from frequently quoted authority,

http://www.sheldonbrown.com/tire-rotation.html

What is important is that best tire should be on front. I am flatted front and rear tires, mostly on rear, whether riding loaded or unloaded. On front, at speed, flatting can be, and has been for me, torn shorts and a bloody rear.

Offline Nyimbo

Re: How to know tire size
« Reply #10 on: February 16, 2017, 05:49:50 pm »
I was just commenting on canalligators comment vs yours dkoloko - probably didn't come out right.

Anyway, I think I agree with you both.  I'm not going to rotate the tires, planning on replacing them.  And yes, if I was going to rotate to extend their miles I think it makes much more sense if I would have done it along the way.  I have been known (by my wife) to wait to long to rotate my car tires

BTW: thanks all for the help in the original question about figuring out tire size options - much appreciated. I'll probably not try all the sizes to see how big I could get - although that makes sense if I had to know.  Perhaps a practical solution would be to just move up to the next size 35mm for my next set and use them for the next year.

Then I can decide next year if I want to try something larger or stay with 35 or return to the 32mm

Offline dkoloko

Re: How to know tire size
« Reply #11 on: February 16, 2017, 07:45:28 pm »
I was just commenting on canalligators comment vs yours dkoloko - probably didn't come out right.

Anyway, I think I agree with you both.  I'm not going to rotate the tires, planning on replacing them.  And yes, if I was going to rotate to extend their miles I think it makes much more sense if I would have done it along the way.  I have been known (by my wife) to wait to long to rotate my car tires

BTW: thanks all for the help in the original question about figuring out tire size options - much appreciated. I'll probably not try all the sizes to see how big I could get - although that makes sense if I had to know.  Perhaps a practical solution would be to just move up to the next size 35mm for my next set and use them for the next year.


As to agreeing "with you both", it is not going to save you from a crash from having a blowout on front tire that the rear tire is as worn as front.

As to trying tire sizes, that can be frustrating and expensive. Your rims are standard width touring rims. 35mm tires should be in the middle to usable sizes, ranging down to 28mm, and up from 35mm.

Offline Pat Lamb

Re: How to know tire size
« Reply #12 on: February 16, 2017, 08:43:12 pm »
I think the best "rotate the tires" advice is to move the front to the rear when the rear tire wears out.

Every now and again I bother to do just that.

Offline canalligators

Re: How to know tire size
« Reply #13 on: February 22, 2017, 10:41:25 am »
I was just commenting on canalligators comment vs yours dkoloko - probably didn't come out right.

Anyway, I think I agree with you both.  I'm not going to rotate the tires, planning on replacing them.  And yes, if I was going to rotate to extend their miles I think it makes much more sense if I would have done it along the way.  I have been known (by my wife) to wait to long to rotate my car tires

BTW: thanks all for the help in the original question about figuring out tire size options - much appreciated. I'll probably not try all the sizes to see how big I could get - although that makes sense if I had to know.  Perhaps a practical solution would be to just move up to the next size 35mm for my next set and use them for the next year.

Then I can decide next year if I want to try something larger or stay with 35 or return to the 32mm

I should have used a consistent description.  By 50%, I meant that the front might last one and a half times longer.  I don't think it would last three times as long.

And as for using a 35 vs. a 32, the difference isn't significant - given the same tire in two sizes.  The more significant factors are whether it has a puncture prevention belt, inflation pressure and general quality of the tire.  Stick to a good brand name such as
Schwalbe, Continental, Maxxis, or other as recommended by a friend or trusted dealer.  As a general rule, avoid tires that have a very low inflation pressure, i.e. 50 psi.  A tire that's made for high pressure has a stronger cord structure.  You don't need to run it at max pressure, but that's another long discussion in itself.

And starting the tour with new tires is excellent advice.

Offline John Nelson

Re: How to know tire size
« Reply #14 on: February 22, 2017, 01:19:21 pm »
I see no advantage to tire rotation on a bicycle. It makes sense on a car, but those reasons don't apply to a bicycle. I treat each bicycle tire individually. When a tire wears out, I replace it. The algorithm could not be more simple. Sometimes a tire seems to go from okay to not okay overnight, so I recommend keeping a few tires on the shelf so that you can replace a "not okay" tire immediately.