Where are the wide rims in DH?

jazzanova · Jun 12, 2015

mojoronnie said:
Who said anything about 1.8? I run a 2.3 on Mavic Deemax's which is considered narrow,and traction has never been an issue. That set up works pretty well for Sam Hill and other top racers. I guess it depends on your skill set and how you ride. But for an advanced rider wider isn't necessary for dh.

Wouldn't you have less contact patch and rolling resistance with 1.8,tires? Don't let yourself to be slowed down by those bigger contact patch 2.3 you are running now...

bing! · Jun 12, 2015

I had Muddy Mary 2.5s, that looked like Maxxis 2.7s. They were grippy but slowed me down on the straights. Backed down to Magic Mary 2.35. On 32mm (28 internal) rims, I don't think I want anything much more if I was not running a wider tire.

djjohnr · Jun 12, 2015

As with everything in life there is a balance point that is pragmatic. Many people find a 2.3" width DH tire (or 2.5" if we're talking Maxxis) to provide a good balance between traction, weight, percision and float, with 2.5" tires (or 2.7" Maxxis) often being too heavy/floaty/impercise in many conditions. With a tire of that width there's no need to go any wider then a 729, and the difference in performance for the same tire mounted on a 729 and 823 is negligible due to how stiff DH sidewalls are. Long story short - there's less need for a wider contact patch since a 2.3/2.5" sticky rubber stiff sidewall DH tire on a 23-29mm internal width rim is already a really good balance point.

mojoronnie · Jun 12, 2015

Tuono said:
If that were entirely true, then Aaron Gwin would be riding slicks. Turns out he rides a wide rimmed wheel and knobbies. Contact patch is another benefit of using a 27.5 inch wheel on a DH bike (see nearly every leading 2015 DH bike manufacturer specs) in addition to rollover height which also improves rolling resistance.
DH is about speed and control. Wide rims help with control. Speed is not entirely about rolling resistance either. With overall fast times, a lot of it has to do with carrying speed through and out of the corners, which requires traction.
Wide rims structurally help straighten sidewalls; which helps give the effect of a stiffer sidewall; which allows for lower air pressure; which helps provide a larger contact patch; which helps with traction in corners; which helps keep speed through corners; which helps with overall speed; which helps in DH.

Speed is isn't about rolling resistance? Did you skip physics or maybe you haven't ridden in the mud. (check bings comment) But You're right, the corners are where you make up the most time. but a good rider knows how to find traction with out going wider. It is all about balance (check djjohnr comment) I ride a dhr 2.35 in whistler and it rails everything I throw at it. When you're hauling A** DH you're not leaning it over that hard anyway

Tuono · Jun 13, 2015

mojoronnie said:
Speed is isn't about rolling resistance? Did you skip physics or maybe you haven't ridden in the mud. (check bings comment) But You're right, the corners are where you make up the most time. but a good rider knows how to find traction with out going wider. It is all about balance (check djjohnr comment) I ride a dhr 2.35 in whistler and it rails everything I throw at it. When you're hauling A** DH you're not leaning it over that hard anyway

Didn't miss physics- also said that speed isn't entirely about rolling resistance. Operative term is "entirely".
We are generally in agreement. This thread is about wide rims, not wide tires. You and I both ride 2.35 tires which are relatively wide. The difference is at the bead not the tread. Wider bead- straighter sidewall- less PSI needed to avoid rim strikes and burps- same tread width- just more of it is in contact with the ground.
You stated that it didn't make sense- I was trying to explain why people are trying wider rims. I have. Went from a 23mm inner width rim with a 2.35 Magic Mary to a 28mm inner width rim and the same tire and was able to drop 5psi and corner noticeably faster. You can try it- or continue to insult people you've never met on forums.

mojoronnie · Jun 13, 2015

Tuono said:
Didn't miss physics- also said that speed isn't entirely about rolling resistance. Operative term is "entirely".
We are generally in agreement. This thread is about wide rims, not wide tires. You and I both ride 2.35 tires which are relatively wide. The difference is at the bead not the tread. Wider bead- straighter sidewall- less PSI needed to avoid rim strikes and burps- same tread width- just more of it is in contact with the ground.
You stated that it didn't make sense- I was trying to explain why people are trying wider rims. I have. Went from a 23mm inner width rim with a 2.35 Magic Mary to a 28mm inner width rim and the same tire and was able to drop 5psi and corner noticeably faster. You can try it- or continue to insult people you've never met on forums.

First off I'm not trying to insult you. It's just an opinion. An Internet opinion for that matter and we all know how those go. I agree with wider rims for all mountain or enduro, but not for Dh. Ride what you like... It's all good

Dpca10 · Aug 2, 2015

To settle this from someone who rides a lot of wide and regular rims. Wide rims absolutely increase traction, counterintuitively it is noticible that on the uphills they actually decrease rolling resistance. Ibis says this is because of reduced deflection with the larger volume.
The benefits are biggest when running tubeless at low pressures
The benefits seem compounded on larger diameter rims
The offerings are almost all carbon because trading these benefits for increased rotational weight would probably lead to mixed reviews.

My thoughts on the pros?
They ride what their sponsors tell them to ride.
Extremely rocky trails like most dh are less suitable for carbon rims.
Dh riders are probably less affluent when viewed as a group
All this equals the pros marketing the standard Alluminum rim. This will change as wide rims get cheaper or carbon rims are more accepted for dh.

zoe07 · Aug 21, 2015

Since I happen to see the thread mentioned "where are the wide rims in DH", will I be allowed to say we have new design rims for DH? The internal width is 31mm, the sidewall is 4.5mm. What width do you guys seek?

man w/ one hand · Aug 21, 2015

zoe07 said:
Since I happen to see the thread mentioned "where are the wide rims in DH", will I be allowed to say we have new design rims for DH? The internal width is 31mm, the sidewall is 4.5mm. What width do you guys seek?

I'm not sure what a good internal width would be, but at least offer it in 26" as well as 27.5" & 29". That way you'll be ahead of the companies in the next coupl'a 3 yrs that are gonna be touting the new & improved 26" wider rims.

zoe07 · Aug 26, 2015

man w/ one hand said:
I'm not sure what a good internal width would be, but at least offer it in 26" as well as 27.5" & 29". That way you'll be ahead of the companies in the next coupl'a 3 yrs that are gonna be touting the new & improved 26" wider rims.

Thanks for your advice, it's right that 26'' is less. Mostly are in 27.5'' and 29''. We've improved one wider rim in 26'' now.

Where are the wide rims in DH?

jazzanova

bing!

djjohnr

mojoronnie

Tuono

mojoronnie

Dpca10

zoe07

man w/ one hand

zoe07

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