Less tire pressure for a wet race?

Triathlon Forum
1

Looks like a lot of rain on the bike split in Ironman Frankfurt this weekend. I am fine with that, have done heaps of wet races before and being Nordic, this is much better than a(nother) hot day in Central Germany 😊

However, now I am running much wider tires than earlier, i.e. measured 26mm / 90 psi front and 29mm / 85 psi rear.

Would you lower tire pressure a bit to gain a better grip on the wet tarmac??
Or is that oldskool?

Expected Avg Speed 39-40kmh

2

Not only do I drop 5-10 psi from front and rear I usually switch from GP5000TTs to standard GP5000s if I know it’s going to be wet.

3

Physics hasn’t changed with the increased tire width ;). So with less pressure your contact patch size will increase and grip will increase too.

4

5-10 psi drop. Ask Taylor Knibb

5

5-10 psi drop. Ask Taylor Knibb

Same here

0.6 bar which is 8.7 PSI

Rumor is some of the Olympic women didn’t drop their pressure.

6

I had a coach who said you ran low psi in the rain because it slowed you down so you didn’t have to take the corners as fast. lol

But yes, depending on the course low psi is sometimes preferable. Easton Twilight Crit this year had an absolute downpour during the national anthem and just about everyone was letting some air out on the start line. That’s a technical 6 corner crit in <1mile, so worst case scenario. For most tri courses I wouldn’t even worry about it. You’re doing 112 miles with probably 50 real corners. It doesn’t make sense to give up 5w of rolling resistance on the 2 miles between turns to save <1second in each turn.

Unless bike handling in the wet is going to make you very nervous. In which case being relaxed and confident is probably worth the penalty.

7

Thanks y’all. Got GP5000 TT TRs now.
Is that of any important risk??
Never had a flat on these.

I get that the standard GP5000 may be more resistant.

Not only do I drop 5-10 psi from front and rear I usually switch from GP5000TTs to standard GP5000s if I know it’s going to be wet.

8

Just use your standard pressure and brake a bit more before you get to a turn.

9

Not only do I drop 5-10 psi from front and rear I usually switch from GP5000TTs to standard GP5000s if I know it’s going to be wet.

TT TR and S TR have the same wet grip score according to BRR. Should be the same compound.

10

Looks like a lot of rain on the bike split in Ironman Frankfurt this weekend. I am fine with that, have done heaps of wet races before and being Nordic, this is much better than a(nother) hot day in Central Germany 😊

However, now I am running much wider tires than earlier, i.e. measured 26mm / 90 psi front and 29mm / 85 psi rear.

Would you lower tire pressure a bit to gain a better grip on the wet tarmac??
Or is that oldskool?

Expected Avg Speed 39-40kmh

Your staring pressure is already very high, btw. Maybe consider dropping much more than 5psi.

Im 85kg and ride my TT TR 30mm WAM at 60-65psi.

11

Not only do I drop 5-10 psi from front and rear I usually switch from GP5000TTs to standard GP5000s if I know it’s going to be wet.

TT TR and S TR have the same wet grip score according to BRR. Should be the same compound.
The reason is puncture resistance.

12

5-10 psi drop. Ask Taylor Knibb

Same here

0.6 bar which is 8.7 PSI

Rumor is some of the Olympic women didn’t drop their pressure.

would you recommend hookless wheels for a rain race …