[MaximusJ]

Hey there,

I'm posting this question here since most people in the modifications section dont even get any snow; so Canadians are the best to answer my question.

To make a long story short, I have to put my car on a dyno next week. But since winter tires are mandatory in Quebec at this time of the year, I got my winter boots on.

How would be the traction with those? I'm pretty sure that i'll lose traction with DTC off because the winter tires are softer then summer tires, but I would like to know if anybody know from experience?

I'm just trying to save the hassle of swapping wheels before and after the dyno, but if I lose traction with the winter rubbers; I guess I wont have the choice.

Thanks for the help

[DESI4life10]

I just did this over the weekend with my winters.

Traction wise it was ok once the tires dried up. As for hp, you will get a slightly lower number, but nothing huge.

One thing I suggest is to not be around the car after it does this pull. Reason being is that is feels like the tires are kinda burning up (like when you do a burnout). Gives off a horrible smell :-). I am guessing this is because of the winter tires being softer as I didn't have this issue with the summer wheels.

Looking forward to your results.

[whoosh]

Depends on the wear on the tires and the compound. My tuner estimates about 10whp loss when running on snows, due to the squishy tread blocks and compound.

Another good reason to stay clear of cars on the dyno running snows: gravel/grit from road clearing that may be picked up in the treads.

[marcvtec]

could be as much as 30 whp less if you are fbo/meth

[DESI4life10]

Originally Posted by marcvtec

could be as much as 30 whp less if you are fbo/meth

He has an NA car which I doubt will lose that much power.

I would say no more than 5 whp

[MaximusJ]

Well since that dyno sheet will be used for promotional ends, I think I will have to bring my summers.

Thanks guys.

[MiroE90]

My 335 lost 12wph between summer and winter tires (274wph summers, 262 winters) definitely makes a difference, from what I was explained by the dyno guys, the reason for the loss is because the tire walls on snow tires are softer and because of the softer walls some of the energy gets lost in the transition versus summer tires which has significantly firmer tire walls and therefore better transfer energy. Numbers definitely didn't lie.

[bradyzq]

You can always do your dyno runs on a hub-mount dyno (Dynapack, new Land and Sea, Rototest). Whatever wheel/tire combo you have will be off the car on the floor during your dyno session.

I have a Dynapack dyno, as do others in the province.

[MaximusJ]

Thanks Brady, but you're 2.5h away ;p

I will definitely bring my summers; since I have to provide dyno sheet to my tuner for promo purposes.

[bradyzq]

No worries!

Not that I have personal experience with roller dynos, but my suggestion would be to inflate the summers good and hard (but within the safety limit on the tire sidewall) to reduce deformation once the car is strapped down.

And strap the car down only enough to be safe and get good traction. No more than that.

Also, if you have the choice, use less sticky tires. Maybe you have some OEM tire/wheel combo in the corner of your basement that are lower performance and narrower than your regular summers? If so, use them.

If you really want to maximize the numbers, a good wheel alignment for the dyno is one with minimal toe and camber.

Enjoy!