[SJ-AK]

Can anyone speak to the difference in speed between D4's and D5's on hard packed trails? I have only ran D5's and would like to know if the D4's are a worthy purchase to gain some speed for upcoming races.

Thanks

 

[jonshonda]

omg such speed, much fast.

 

[tims5377]

omg such speed, much fast.

lol

4" tire is always going to have less rolling resistance than a 5" tire with a similar tread, similar compound, similar pressure, similar trail etc.

Faster depends on more factors such as traction and trail conditions.

 

[SJ-AK]

I realize it's all relative, but if 4's give you another mph on packed city type trails then it may be worth the investment for me. I am attempting to glean that from forum members who may used both or preferably raced them.

Thanks.

 

[RockyJo1]

I'm sure you could calculate that out if you know the contact patch rolling resistance and the weight of each tire.

 

[the mayor]

I have both. I run the 4s on 65mm rims and the 5s on 90mm rims. So not really apples to apples.....but
Is there a speed difference?
Not really. Maybe...depending...
Is there a ride difference?
Yes! Huge difference....if it's packed and smooth, the 4s are fine. If it's packed and bumpy...the 5s go on.

 

[wrcRS]

There is a speed difference. I've ran 4s and 5s on the same width wheel and have found that over 12mph the 5s start to require a bit more effort. My opinion is if the race is important to you then I suggest getting 4s. If it isn't that important to you then just run the 5s.

 

[SJ-AK]

There is a speed difference. I've ran 4s and 5s on the same width wheel and have found that over 12mph the 5s start to require a bit more effort. My opinion is if the race is important to you then I suggest getting 4s. If it isn't that important to you then just run the 5s.

Thanks for the feedback, that is what I have heard from another as well. You don't see to many folks running 5's outside of backcountry ultra's. At least not that I have seen up here in AK. I figure there has to be a reason for it.

 

[Jayem]

I figure there has to be a reason for it.

The reason is they can't get them, they are expensive, and they only know what they have. It's hard to get rid of a perfectly good tire when even 4s last season after season if you just ride them in the snow (my 5s are on the 3rd season). I don't find that the 5s slow me down for races. I did build up a wheelset for 4s recently, but I've raced extensively on 5s and I gotta say they are pretty great. I've nailed several top 5 finishes in races and I never felt like the tires were holding me back. In fact, I don't know if it's just me, but I feel I can pedal through turns easier on the 5s, where I see a lot of other people coasting.