Crit question - tire pressure

[FastforaSlowGuy]

I'm far from being race crazy, but I'll do a handful each year (5-10). Generally this means road races, but I'm thinking of doing some crits this year. I've heard some guys run slightly lower tire pressure to gain a bit more traction in corners. Anyone do this? Does it seem to matter? I generally ride 23mm tubulars with 105 pressure, at 160 lbs., which has been fine. But I rarely am diving into sharp turns with 75 guys the way you do 4-8 times per lap in a crit.

Thoughts?

[Peter P.]

I see no reason to vary tire pressure for criteriums versus road races. I never did.

I think you actually might want to experiment with even lower tire pressures than you're currently running.

[Chris]

I'm 170. I run 90 in 25s

[shovelhd]

I run the same pressure for road races and criteriums, but I vary the pressure to match road conditions. My normal pressure is 105/100 but I will air down if the roads are crappy or wet.

[Shortsocks]

For me it depends on what the condition is and what time of the year.
In Texas/Oklahoma it gets ridiculous hot in the summer, and a lot of the crits are towards the end of the day where the ground is very warm.

It just varies. If I'll be doing a road race, it depends because there is a lot of chip seal and that Sh*t melts and gets very sticky.....

[Tandem Rider]

I'm also 160, I run 110 and 105 on good surface. Less if it's rough, more less if it's wet. I race on tubulars.

[AnthonyC]

As most folks have said, let out air if the road is wet. Otherwise, normal pressure. You might consider going to a 25c tire and running it at 90-100psi; negligible gain in rolling resistance/weight combined with a cushier ride and better cornering.

[ultraman6970]

IMO over 100 with tubulars is ok. if you run like 80 psi with tubulars and if your weight is high like in the 200 pounds, what you get is not a traction problem, it is a problem with the tubular getting deformed too much in the curves and standing up while coming off a curve or even in the straight parts while standing up in an attack.

I would lower air pressure if the road is bad or if a section of the race is grable (sp) but in a criterium ? no way. You will lose speed in the curves if you go with less air.

Good luck.

[RacerJRP]

i run the same pressure for road races and criteriums, but i vary the pressure to match road conditions. My normal pressure is 105/100 but i will air down if the roads are crappy or wet.

+1

[carpediemracing]

Arg. I had a response ready to hit "Submit Reply" and my mac went down. Apparently you shouldn't be uploading race flyers to USAC, replying on pace line, and have a few other tabs open (as well as a bunch of apps etc).

I run higher pressures than the answers that I see before me. I'm about 170-185 lbs and I'll run 120-130 psi regularly. At 160 or a bit less I would do 1110-120 but for the faster, less turn-y races I'd still run 120-130 psi (typically 5 psi less up front).

Remember that tubulars only rely on their constructed width, unlike a clincher whose effective air volume is determined in part by the rim. Only reduce tubular tire pressure if you're going with a wider tire. The rim inside the tire doesn't really affect tubulars like it does clinchers.

So for me a 21-22mm tire needs about 120-130 psi. A 23mm tire, which I use now, I run 5-10 psi less (but in all honesty I really can't tell the difference).

On the other hand my 700x23c clinchers get anywhere from 65-105 psi. If I know I'm doing a particular loop with two very hard turns then I'll do higher, like 85/90 psi minimum, because I had problems going around one of those two turns at 65 psi. I also had problems when I mistakenly raced at about 90/95 psi on 22mm (I think, I'm pretty sure they were 22mm and not 21mm) at the Tour of Somerville (watch the third turn in the first lap and last lap (http://www.youtube.com/watch?v=Ey2zLZwm1w4)).

I'm sure part of it is my old fashionedness. Some bike tire company makes a radial tire, which, if you're familiar with tire construction, will lead to a much softer casing. All normal current car tires are radial, at least in the US, but truck tires and other heavy duty tires can be bias ply, the same type of construction of most bike tires. Bias ply tires are stiffer and feel very different. I think I wouldn't be a good mix with radial tires, at least on the road, because it'll be so soft. A German journalist either crashed or almost crashed on the radial tires and immediately wrote them off. The journalist that wrote the article gingerly rode them and basically said that they're so soft they felt flat, but that subjectively he felt they should have an advantage.

I'll stop there as Junior is melting down. :)

[shovelhd]

My numbers were posted for clinchers, assuming that's what the OP was running. Add 5-10 pounds for tubulars. Definitely. I also run narrow rims and tires.

[Tandem Rider]

IME the biggest worry about pressure in a race is keeping the tire from folding over, losing traction and then "walking" sideways in a corner. Clinchers seem to be more prone to this than tubulars. This is a really bad thing when you are shoulder to shoulder in a corner at 30mph. Wet surfaces have less traction and therefore are less able to fold the tire over.

Higher pressures don't automatically mean less rolling resistance, they are only faster on smoother surfaces. The "feedback" through the bars makes it always feel faster though.

If your big concern in a 1 hour event is ride comfort you aren't racing.

[jamie789]

How would this translate to 23 clinchers on a wide (23mm) rim?
Maybe 80-90 for someone weighing 155-160lbs?

[carpediemracing]

How would this translate to 23 clinchers on a wide (23mm) rim?
Maybe 80-90 for someone weighing 155-160lbs?

It really doesn't, which is part of what I learned with the 23mm rims and 23c tires. The tires are larger than my 23mm tubulars. I have less clearance to the frame with the 23c clinchers.

On my normal loop there's a hard left turn at the bottom of a hill. I hit it pretty fast, I can see if it's clear, and I normally go through there at 30 mph or so. Over the last few years I've tried it at different pressures. At first I was really skeptical regarding the low pressures so the first year (2010) I never went below about 95 psi.

Then I had a chance to try the tires at about 70 psi. I slowed pretty dramatically for the two left turns I made on that ride (it was in Vegas) but I realized that the lower pressure wasn't that bad.

At that time I was 160 lbs, maybe a little less.

Then I both gained weight (back) and tried lower pressures. I went out with ~65/70 psi on the tires once and almost went into the field on my normal loop's first left turn. The tire wouldn't turn. I realized that I'm not used to the soft tires and honestly I didn't feel like learning/acclimating to it. I guess I'd be more like the German journalist than the very game English/American one that really tried the radial clinchers.

Since then I've entered races with 95-105 psi if I'm on the clinchers, typically in the rain or a Tues Night crit which has two decent corners on it. If I don't know the route or I think I'll need to corner hard (crit, particular downhill corners/turns) then I'll go out at normal pressure, i.e. 100/105 psi.

My weight has fluctuated from the low 160s (early 2011) to 185 (early 2013) to 170 (now). I also love to corner, it's the most thrilling part of racing, to corner on rails shoulder to shoulder with other riders (I think of it as cornering in formation). For better or worse I'm trained to corner with high pressure in the tires.

[AnthonyC]

Yeah, I take back what I said above, given that I was talking about clinchers and I see now that the OP is asking about tubulars.

Thanks for dropping the knowledge, carpediem.

[carpediemracing]

Thanks for dropping the knowledge, carpediem.

Thanks, but please keep in mind I have my preferences/biases (I can't think of the word at the moment but it'll come to me). For example I could see how softer tires would work in certain situations, having run very low pressures when riding mountain bikes, but I have a bias towards higher pressure when it comes to crits.

I'm not courageous or patient enough to try wider tires at lower pressures, at least not right now. I have a pile of 23mm tires waiting to be glued (I need to glue five tires for the season and I think it'll leave me with 5-6 new and maybe 8-10 lightly used tires left over). I don't have the luxury of trying out something different. I used to try things (17-18mm tires on 17mm rims in crits at 140 psi when I weighed 110 lbs, etc - watch Chiapucci in the final TT of the 1990 Tour for reference) but now I tend to be equipment conservative.