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Transitioning from XC to AM

4K views 19 replies 9 participants last post by  Harold 
#1 ·
I've raced road bikes and XC bikes for many years. Lighter and faster was always the rule. I just entered my 6th decade and short travel XC bikes are starting to get old and my desire to race XC is waning. Longer distance fast paced rides with my wife are now the order of the day.

I currently have my 2016 Roval Control SL's (26mm out/22mm in) with 2.1 Schwalbe Rocket Ron's from my XC bike on my new 150mm dually. I climb almost as fast on it, but it feels undershod in the wheel/tire dept. The better suspension allows me to load the tires more and they feel like they're distorting around the narrow rim.

I'm looking at a set of Light Bicycle AM wheels with 39mm out/33mm in rims and moving up to 2.25 Rocket Ron's to get paws more in line with the suspension.

Thoughts/comments/recommendations appreciated.
 
#6 ·
Appreciate all the replies.... some good info here. I got spoiled climbing and rolling around on XC gear and really didn't want to move to something that felt like pedaling in mud.... the Rocket Rons are fantastic multi-purpose tires. Wish they made them in 2.3-2.4. But even their 2.25 is really small for size.

Guess I'll just have to try some things. The thought of having a nice meaty tire up front is really appealing.
 
#8 ·
Take a look at the bontrager XR4. It's a lighter version of the se4. personally I run the se4 out back(850g and I consider that fairly light)) but you're looking to save weight. If you want even faster rolling you could look at the xr3. Just get it in 2.4 size or so. Larger tires with less air pressure is what you're shooting for on that 150 mm bike. You'll be surprised by the enhancement of handling and traction in tough terrain compared to skinny tires with higher pressure. Sounds like it's just a mindset you need to move past. Trust us, lol.
 
#9 ·
Sounds like it's just a mindset you need to move past. Trust us, lol.
Not the first time I've been here, lol.... Been riding MTB's since they were invented (grew up in the Bay Area) so have gone through quite a few fads and changes over the years. I'm naturally slow to change, unwilling to spend money needlessly and like to let others figure out what works and what doesn't and then adapt. So yes. Spot on. This is probably another one of those junctures...

I just recently made the move from a road race road bike frame with high pressure clinchers to a gravel frame with 32c tires at 50/70psi and am blown away at the difference. No loss of speed, but incredible handling and comfort improvements. My guess is that we're talking about something similar here.
 
#10 · (Edited)
Update on this....

Got my wheels. 31.4mm IW. Mounted a set of Bontrager XR4 Team Issue 29x2.4. All I can say is.... WOW. The size/volume change is monumental in regards to feel. Better small bump performance. A LOT more confidence in corners. Reduced fatigue due to less rattle.

A huge step forward. Thanks, guys.
 
#11 ·
Update on this....

Got my wheels. 31.4mm iD. Mounted a set of Bontrager XR4 Team Issue 29x2.4. All I can say is.... WOW. The size/volume change is monumental in regards to feel. Better small bump performance. A LOT more confidence in corners. Reduced fatigue due to less rattle.

A huge step forward. Thanks, guys.
^ :thumbsup:
 
#14 ·
Update and a question...

Got out and rode these again day before yesterday. 18F/21R and they seem very good. But I have a question about tire width/rim width/air pressure. These are the 2.4 XR4's and the rims are 33mm iW (I think I misspoke above). It's really hard to tell what they roll like right now because the conditions are crap. But a friend of mine raised concerns that this tire was not designed for wide wheels and won't function as designed, namely excess drag due to premature engagement of the side knobs. I did ride across some pavement after my ride to get to my vehicle... it's hard to tell from these photos, but the side knobs are *just* getting the corners cleaned off from straight riding...

Is this something I should be concerned about? I know that rounder XC tires were sketchy when trying to load the front tire, so from that standpoint, I kinda like the idea that the side of the tire is easier to get to.....

Thoughts?
 

Attachments

#15 ·
https://www.lightbicycle.com/newsletter/tire-size-chart-for-bicycle-rim.html

https://www.wtb.com/pages/tire-rim-fit-chart

https://www.maxxis.com/wide-trail-wt-design

https://www.theproscloset.com/blogs...he mountain side, our,for a 40mm internal rim.

https://www.notubes.com/stans-tech/wide-right

Read these articles and draw your own conclusions.

I ride 3.0 tires on my 35mm Ibis wheels on a rigid SS and 2.5 tires on SC Reserve 30mm wheels on a 130/120 geared bike.

As you know, everything can be a trade off. The more challenging the terrain, the more burly of a tire you might want and they will weigh more and have a bit more rolling resistance often times.

I don't roll on Schwalbe stuff because they are too delicate for our surfaces, even most of our XC stuff with a few exceptions. I roll on Maxxis and LOVE them. I used to XC race a good bit and no longer have the desire to participate in those events. I ride mostly techy, chunky stuff these days--big climbs and big descents. Rolling resistance is a bigger factor to me than weight. The tires I generally run are either Minion DHF WT 3.0 or Bonty XR2 3.0 on the SS and Maxxis WT Assegai and WT Aggressor 2.5 on the Tallboy 4. I don't get the Double Down casings in any of these Maxxis tires. Of course they are always tubeless.

Good luck and have fun!
 
#17 ·
I received your PM but thought I would reply here.

I don't know you, how you ride or where you live, so an answer might be somewhat difficult. However, in my estimation, a 33mm internal width rim should roll a 2.5 or 2.6 tire designed for that internal width. Smaller tires aren't taking advantage of possible air volume and could deform the OEM tire shape too much. Read those articles and you will see what I mean.

I weigh 200# ready to ride with a full camelback, shoes, helmet, and cloths. On the 3.0 tires I run 13-14# in the front and 14-15# in the rear. On the TB4 I run 22-23# front and 23-24# in the rear. I live in northern New Mexico where we have mixed surfaces of chunk, kitty litter, loose gravel of various sizes and sharpness, hard pack, but not much roots, loam or water.

There was a really great interview with Nino Schurter where he talked about tire pressure. He put his thumb over the tire with his other hand covering it and then added his full body weight down to see if he could touch the rim with his thumb. He suggested going as low as possible with tire pressure. And that dude can ride techy stuff like mad! Haha!
 
#18 ·
All good info... I'm not super aggressive and weigh #210 kitted. We have anything from hardpack to straight up rock gardens here... but I tend towards the less technical and Big Air for me is an inch. ;)

I have these now, so I'll give them a go. I was thinking of mounting XR2's for a gravel race next fall. When I say gravel, think blown out double track with baby heads and rocky single track and about 15 miles of pavement. Would you think those tires good for something like that? Looking for low rolling resistance there....
 
#20 ·
FWIW, I've had pretty good results using 29x2.6" tires on 30mm inner width rims. It's probably about the biggest I'd want to ride on that rim width. I chose 30mm because I wanted to run tires 2.35-2.6" wide.

This follows with the WTB chart already posted above.

Also fits with the DT Swiss chart in the manual for the XM481 rims I'm using.


0321191201 by Nate, on Flickr

I'm in the 180-190lbs range kitted up, and I go to around 12psi F/16psi R roundabouts.

In the past I rode a fatbike year round which went way to the extreme on tire suppleness (a bit too far for the way I like to ride in the summertime, anyway) and introduced undamped tire bounce. You won't catch me going back to sub-2.4ish tires (shoot, I was using 2.4's on my 26er with 19mm inner width rims) for mtb purposes that's for sure.
 
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