3

I recently replaced the both tyres on my tourism bycicle, going from a semi slick pair to a threaded pair, but keeping the same size, 700 x 28c.

The semi slick I had were these

enter image description here

while the new I have are these

enter image description here

Since then I have noticed a different behavior when I bend to turn.

While with the old tyres I had to "push in the curve" to keep the bike into the turn, with the new tyres I have to "pull out the curve" to keep the turn. In other words, with the old tyres the turning bike had the tendency to go back straight, while with the new tyres it has the tendency to close the turn.

Is this normal and will fade with some wear of the tyres, or do different tyres affect the bike dynamics?

8
  • It sounds like you're talking about countersteering? You'll still countersteer regardless of the tread once you exceed some not large speed (you can't turn otherwise). But tire rigidity, grip and other factors of the tire do affect how well you corner.
    – Batman
    Mar 3, 2017 at 8:33
  • A semi-slick* tyre will have a cross-section that's effectively an arc in the relevant area. The more tread you get, the more the tyre has a shoulder, and cornering on the shoulder will be slightly different. Then there are hybrid tyres which are almost slick up the middle for low rolling resistance on the straight but have some tread on the shoulders for dirt roads etc. Anecdotally, I found the cornering changed from road cruisers to marathon plus (both with minimal patterning, but also a change in width from 35->32mm) possibly due to the harder compound. *Definitions of semi-slick vary.
    – Chris H
    Mar 3, 2017 at 9:22
  • 1
    Is the pressure you run in the new tyres different?
    – zeFrenchy
    Mar 3, 2017 at 9:52
  • 1
    In a 700x28, the tire with the heavier tread will be effectively wider (actually by quite a bit, in terms of the amount of tread touching the road), and a hair taller as well. There will also be differences due to the way the tire "grips" the road. Mar 3, 2017 at 12:53
  • 2
    The profile of the tire will also have a big effect. The old tyres are fair rounded on the shoulder. The new tires have quite a pronounced shoulder.
    – mattnz
    Mar 3, 2017 at 21:18

1 Answer 1

4

You should read up on bicycle handling dynamic to understand how various elements influence how your bike behaves during cornering. You did not provide the actual sizes of each tyre, nor the pressure you use in them. My guesses to explain why your cornering has changed so much would be:

  1. Your new tyres have a significantly bigger outer radius, hence affecting the trail of you bike.
  2. Your new tyres run at lower pressure and are therefor flexing more when leaning in corners.
  3. Your threaded tyre offer increased grip on the edges, while your slick have a reasonably constant grip regardless of leaning angle.
3
  • I edited the question including the tyre size.
    – L.Dutch
    Mar 3, 2017 at 11:54
  • 1
    I still can't find any trace of a 25c version of the threaded tyre you mention ... not even on the shwalbe website (schwalbe.com/en/tour-reader/marathon-mondial.html). Also the tyre linked above shows 55-85psi as the pressure range, which is significantly lower than any 25c slick I know of.
    – zeFrenchy
    Mar 3, 2017 at 12:06
  • I looked back into the invoice, the new tire is a 28 x 1.1/8 (28-622)
    – L.Dutch
    Mar 3, 2017 at 12:15

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.