650b+ (and other plus sizes if you like) – rim, tyre, frame, fork combinations,

OK, useful to know thanks. May well try it to start with as most tyre choices are currently 3.0 or less.

I was out last night with standard 29er skinny tyres and god, I struggled. Maybe I was just having a crap day but I couldn’t keep the bike going where I wanted. Wondering if I’ve got used to the heavier b+ wheels (though I didn’t notice any adverse handling when I switched) and now going back to lighter ones is making the bike feel too twitchy…

Riding 4″ fat all winter and going back to a 29er does take a bit of conversion time. I’d imagine a similar effect.

Yeah, quite possibly – it was just a bit of a shock since I didn’t really notice the switch the other way.

Or I was just riding like a muppet last night…

Yes, I test rode a Solaris with crests on after 8 months of exclusive fat bike riding & it felt like I’d never ridden a bike off road before, absolutely no confidence & cornering was like bambi on ice

I have to echo the above. I spent some time riding with a fat front end last winter and I sold it because it was doing my riding no good.

rOcKeTdOg – Member
Yes, I test rode a Solaris with crests on after 8 months of exclusive fat bike riding & it felt like I’d never ridden a bike off road before, absolutely no confidence & cornering was like bambi on ice

Skill compensators, these fatbikes. 🙂

Compensation welcome here.

The comparison with a 4″ ‘trail’ fatty is interesting, I was pretty close to buying a Canyon Dude before I decided to give b+ a punt. If it works out then I’m £1500 ahead and have got an upgrade in under the wife-radar without triggering n+1 issues.

25mm internal are fine for 2.8″ TRs

How would 23mm ones fair? too narrow?

How would 23mm ones fair? too narrow?

Tough call, it’s only 2mm …

I’m pretty sure you’d be OK for fit-testing and bouncing off the curb, but I would stop there. There has to come a point where the risk of a burp starts to increase dramatically, tho I don’t know where that would be.

In the similar vein I once ran Hans Dampfs on Crests but they come up very light-bulby and I decided not to do it again, I stop at 2.3 on Crests now.

honourablegeorge – Member
rOcKeTdOg – Member
Yes, I test rode a Solaris with crests on after 8 months of exclusive fat bike riding & it felt like I’d never ridden a bike off road before, absolutely no confidence & cornering was like bambi on ice
Skill compensators, these fatbikes.

I need all the help I can get

After trying a bizango frame with 650B+ which worked, but mud clearance was tight I really like the way it felt with TB rear, Purg front. So decided to ‘invest’ in Stanton Sherpa frame – there is a ton of clearance for the TB on 25mm ID rim – I think could go with a proper wide rim and wider tyre most likely. Either way, I am loving it. The Fox 32 fork fits the purgatory really well because of the shape of the tyre on the 29mm ID front rim. Looks closer in photo than it is – approx 5mm clearance. No rubbing at all. Just loads of grip on rocky rooty descents, very flickable, easy to pick the front end up. Chuffed 😀

3.0 purgatory won’t go into revelations forks. It would have a couple of mm each side if it sat centrally…. Which its not atm

daveski1000, that’s pretty much the exact bike I wanted to build… very nice

On that, the Suntour Epicon fork I was running before, was surprisingly good, though I added a shim to air chamber to make it more progressive – it’s too linear otherwise. Had loads of clearance for the Purg, I can’t imagine there’s a better 29er fork for 650B+ for fit alone. Performance is another matter of course.

thepodge, thanks – it is so capable, I did a 500m descent on it today that had a bit of everything – rocks, roots, tight switchbacks, fast open singletrack… The confidence it gave was amazing. To add to that, I had the 500m climb at the start – no problems, just grip. Overall, so planted. Maybe finally found a keeper, for a good while at least.

Actually, with some playing I’ve got 7mm clearance between the fork (revs)and tyre (3.0 purgatory) (shared between both sides) the tyre still isn’t perfectly centred and sways a little. It’s not ideal ,its just that bulge by the seals.

29″ wheels have gone back in for now, going to do the same ride as last Sunday to compare

Actually, with some playing I’ve got 7mm clearance between the fork (revs)and tyre (3.0 purgatory)

not what I wanted to hear, I was hoping for a little more between the fork legs as that’s what I have on my Solaris 🙁

just trawled through the thread and noticed your on 38mm wide rims, is that right alexh?

Yes, 38mm rims.

It’s a shame as I think that’s a dam good tyre. Well rounded, good side knobs and doesn’t self steer

quite big rims then, I was wondering if a narrower rim may help with clearance

A couple of mm maybe but not masses. My understanding is wider rims mostly make the tyre taller, with the sidewalls straighter and less curved, rather than significantly wider.

AFAIK the major advantages of a wider rim are better tyre support so less chance of a burp, and more volume so pressures can be lower.

I really want to try the Purgatory but can’t justify £45 just to try.
I’ll be running i35’s on either Pike or Revs. 7mm at the sidewalls sounds fine. My stooge had the same clearance and it worked fine on my local rides.

What’s the chance that the local Specialized concept store will let me try..

For info, I was running a 2.8 TB on a 23mm internal rim. No burping issues running ghetto.
Now on a Dually. Ride wise it’s not noticeably different, but the tyre takes on a much squarer profile.

23mm rim…
IMAG0119 by pten2106[/url], on Flickr
Untitled by pten2106[/url], on Flickr

Dually (45mm)…
Untitled by pten2106[/url], on Flickr
Untitled by pten2106[/url], on Flickr

(Not got round to trimming the ghetto tube yet.)

The purgatory has grown a bit too. The only way it will have any clearance to revelations is with a trim to the side knobs.(the carcass size is ok but the side knobs protrude to a point that’s exactly where the bulge is) . Being as its now a useless 45 pound tyre to me, I’ll probably trim the side knobs, but I’d advise not to buy this for revelation 29″ fork.

Nobby nic/ rocket Ron’s are due soon in 2.8 from chatting to my lbs

Cokie, that was 7mm shared between both sides. It appears to wobble a bit at present. So 5mm one side and 2mm the other (it’s now grown enough to physically touch the fork this am and won’t turn) I’ll try reseating the tyre and trimming it. I think its a no for revs and pikes.

I think its a no for revs and pikes

bugger 🙁

how was that WTB on the 23mm rim takisawa2?

alexh- thanks for clarifying! Saved me hassle and time.
I’m now wondering what aggressive mud tyre will fit.. a stretched DHR or HRII?

To be honest, putting the 2.8 trailblazer next to my maxxis 2.35 hr2 on flow rims…there wasn’t much difference. A good 2.5 dh tyre is probably similar.

Alexh, I’ll buy the purgatory off you if you’d sell it as I’m about to buy a new one and it’ll fit my rigid fork fine. Email me if so.

http://i1273.photobucket.com/albums/y413/paulwatterson/image_zpsgkallf9h.jpeg

You know, this picture cemented somethign I’ve suspected for a while… We need a slightly bigger rim size 😆 A bigger rim would equalise wheel height with equivalent 29ers and put the tyre in the widest part of the fork. Someone get on the line to the Bike Industry Secret Hideout.

Hey, maybe if 27.5 had actually been halfway inbetween 26 and 29, it’d work better 😉

^ crazy but true.

Nemesis, I’ve just trimmed a bit off each side of the tyre so no use to you.

Anyway, I’m going back to 29″ and testing. If it’s unfavourable I’ll probably just sell the hope/light bike carbon 38mm rims and tyres I have off.

650 A+ anyone 😉

I’m just waiting on a warranty cassette, then I’ll be able to test if a lightly shaved 3.0 purgatory will actually ride. Clearance looks the same as the Trax fatty now (2-3mm) at pinch point. I’ll post a photo too.

View post on imgur.com

I think it will spin and work now I’d trimmed the side knob shamfer closer to the casing. Showroom clearance at the pinch points though.

3rd shot is of the un inflated Trax fatty next to the purgatory. Quite similar, but the trax doesn’t give a uniform round profile once inflated, which is my gripe with it. I suspect it needs Hugo wide rims to make it more uniform

Mk1 Yelli Screamy, WTB i35 rim, Trailblazer at 15psi – in the stand DS chainstay clearance is in the region 2.75mm (a 2.5mm hex clears with no contact, a 3mm goes through easily but with contact). Clearance on other stays and to seat tube is noticeably more, I didn’t measure.

It looks bigger than it sounds, I think it’s rideable but I can’t ride at the moment.

By eye, the tyre carcass is wider than the tread, and I measured it at about 64mm (2.5 inches) with a tape. ’67mm’ is embossed on the tyre, that’s on a wider rim perhaps.

That will rub I reckon – My lurcher has a bit more clearance than that and the stays showed clearly that they tyres had been rubbing slightly (polishing rather than actually wearing through but it was dry and just one ride – more riding would no doubt eventually start to wear the frame and/or tyres).

It doesn’t. Same frame/tyre but a wider rim. No issues in the 100 miles I’ve done. The pinch point on the frame coincides with the sidewall of the tyre where there is no tread, and holds no debris. There is plenty of room elsewhere where the tyre has tread.

Interesting. I must be more radcore then 😉 (it’s the sidewalls, not knobblies that rub on mine too)

How stretchy are these tyres? I hadn’t given it any thought til I discovered my Bud has (sort of) adequate clearance at riding pressure but jams solid against the frame at higher pressures. With 25 or 50 psi in normal tyres it doesn’t seem to make much difference, like they’re already stretched to the max but fatbikes seem to operate in the area where the tyre’s still growing, made me wonder if B+ is the same.