[Closed] 650b conversion

Would the tyre still clear the seat tube at full travel?

Will obviously check before riding 😕 (am currently contemplating before buying) but as above HDs are coming up at just over 27 so if using not too big tyres, assuming should be okay

But if they are pretty much the same overall size, (big 26 tyre vs small 27.5 one) you start running in to the what's the point? Conundrum, Shirley. Upgrading to 27.5 only works as an upgrade if you use the same or similar size tyre. (Assuming you see it as an upgrade, of course.

Tom - I did sort of explain the point (and anticipated "what's the point") in my initial post.

...ie. similar or slightly more rollover - less rotating mass

Apparently you will be a lot slower as well.scientifically proven.

Scientifically not possible for me to go a lot slower

Ok, so why not get a similarly sized, lighter tyre? I'm assuming you are already running tubeless?

The reason I say that is the rolling ability of 27.5 over 26 is pretty negligible anyway, so if you want lighter eheels first and foremost, that's what I'd do.

Yes I am tubeless. I'll try and explain what I'm doing (it's a sort of thought experiment until I actually try). I have smaller tyres - 2.1 & 2.25 Advantages. The big HDs roll better. This may be because of the volume. Or because of the outside diameter (26 for 2.1 Adv, over 27 for HD). Or maybe both. However the extra weight of the big tyre is noticeable.

I reckon I could get up to an OD of 27.5 before fouling. So I could get an even bigger tyre - 2.5 maybe, or try a 2.1 on a 650b. The latter, especially on a wide rim will still give me decent volume but most of the extra space is being taken up by lightweight alloys rather than heavy rubber. If its better - I'll say so. If not - I'll say so.

Don't fancy really big lightweight tyres. I killed a couple of S-works Ground Controls last year 😥

Ah, interested to see what responses you get, as I've just bought a Blur TR frame 😀

Out of curiosity, I did a bit of scouring online to investigate converted Blur TR's and it looks like there can be some seattube-tyre issues with things like 650b Hans Dampfs (which is the type of tyre I'd be looking to fit).

As far as the Roval fatties go - if they're the carbon version you're thinking of, I'd strongly recommend trying to get a ride of a demo bike with them fitted, as I got a pair of the 29er Roval Traverse carbon wheels (supposedly AM wheels) about 12 months ago, and was a bit disappointed. Although the tyre profile is good, they're not as laterally stiff as even something like a well built Arch EX wheel, know this years Roval rims are wider, but they've also decreased to spoke count ( I guess to hit a weight target) - I've seen a review somewhere (MBUK?) that mentioned the slight softness of the new Fatties. Er....I guess all the above depends on your weight, riding style, terrain yada yada.

Anyway, good luck with the conversion if you go for it

Hi Bowglie. Am planning on trying something cheap'n'cheerful, second hand first then if it works get something decent. I seriously doubt 650 Hans Dampfs will fit (at least not without reducing travel which I don't want to do). Prefer to try things out for myself rather than just listening to magspeak. For example 50mm stem with 750 Havoc bars didn'd do it for me. Changed to 85 with 711 carbon Haven and it's perfect. I'm unfashionable but happy.

Hey Andyman, the second-hand approach sounds like a really good plan - and I'd be interested to know how you get on if you try a wide 650 rim and 'normal' volume tyres.

P.S. Glad I'm not the only 'anti fashion' going back to longer stem and narrower bars - I really tried to like the 35/800 combo. but it just seemed to emphasise the shortish cockpit size on my SC (TB Lt); bike seems to handle far better with 70/750.

Different beast altogether but I've done 650B conversion on my Prophet some time ago. BB went up a bit, traction seemed to be marginally better and in the result I've managed to drop some weight with new wheels. I've squeezed NeoMoto 2.35s, Blur TRC is apparently even roomier to play with bigger tyres/wider rims!

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vs

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Bottom line: if you have spare coins it's well worth checking how it'll change your ride. Bear in mind it'll affect the bike's geo though!

Not sure if you've spotted it but there's a pretty lengthy thread on mtbr about this exact subject. [url= http://forums.mtbr.com/santa-cruz/650b-trc-774512.html ]Here[/url] 😀

Fathomer

I've seen that thread. Many of the clearance issues relate to the rear tyre catching the FD cable. As I'm running 1x11 this isn't a problem. Still need to be careful though (and don't think I have the balls to somehow shave off the cable guide - which is so perfectly in the wrong place for this experiment).

Kazafaza

Apart from BB height, geo will not affected at all - which is sort of the point as it's just right! BTW I have (and use) a 2005 Scalpel. Still a great bike 🙂

I can see an argument if you want the larger diameter using a light weight tyre and wheel. Opposed to a large volume draggy tyre.

I think your first step would be to find a few willing mates and borrow some 650b wheel with different tyres on to see what you've got width clearance wise. My Blur LTc isn't exactly roomy at the back.

I saw a Blur TRc with 650b wheels in the Surrey Hills once. I also spotted the line of missing paint up his seat tube. While you've got a mates wheel deflate the shock and see how close you are at full travel.

New wheels, tyres, forks? This is an expensive operation. Especially if you end up with a limited choice of tyres and something that clogs up easily in the mud. Is it really worth it?

The equivalent 26" wheels and tyres of whatever you choose in 650b will be lighter. This might be more noticeable/better appreciated.

26" wheels are better for changing speed and direction anyway 😉

Hey babyfood (SMA - geddit ) you understand what I'm trying. If I had mates with suitable wheels I'd try that but no. So will try something ebay cheap and sell on if no go. I'm not convinced that slightly bigger wheels will be better but open minded and want to try for myself. Short to medium term I'm considering carbon wheels (possibly Light Bicycle - widish rims ) and need to be confident in what size to get. Forks also will remain at 26. Geometry is currently dialled for me and don't intend to screw it up with longer A to C.

Is it really worth it? Don't know yet. If I don't think so I'll be buying new 26 wheels happily free of that nagging what if. And changing speed and direction is quite useful whilst mountain biking 😆

If you have 26" Fox forks they will happily accept 650b tyre:

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