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My 2011 Sworks Epic...should I convert it to 27.5


jbsp1's picture

By jbsp1 - Posted on 10 May 2013

I am seriously thinking about converting my 2011 Sworks Epic to a 650b. Have found images of same bike with conversion done. Clearance seems ok on both front and back with ZTR Crests and RRs.

What are your guys thoughts on it. Can get Crests on Pushys at the moment for $329.

No other changes needed so can flick between 26" and 27.5".

[Mod. moved to MTB gear]

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hawkeye's picture

Unless you're planning on running a reeeeeal skinny rear tyre, I don't see that you're going to fit one in the rear with that seatstay bridge so close to the current tyre with the 26" rims. Since the object of the exercise is to run bigger rolling diameter wheels, I think you're out of luck.

Same on the front if you want to keep the brain fork.

I've seen it done on a Cannondale Rush and a current gen Scalpel 26er by the guys at City Bike Depot. They had to reduce the Lefty fork travel a little so the tyre wouldn't hit the bottom of the steerer - all good.

It's cheaper and almost as effective to run bigger bag tyres if you can fit them. According to the guys at CBD, there's little difference between running a 2.4" on a 26er and 650b with a 2.1"

kitttheknightrider's picture

Are those pics of your current set-up or of someone else's converted bike?

If they are your current set-up then I am with hawkeye on this and not worth it. You won't have enough clearance to get any benefit.

If they are someone else's set-up and your frame has bigger clearances than that then I would say yes, go for it. You want to make sure that it won't just clear seat / chain stay bridges but also that it won't hit the seat tube when the shock is compressed. Alos drop all of the air out of your fork and make sure the crown doesn't drop below the arch or you may need to add a travel re-stricter as John has mentioned. If you can get away with it then it is a great upgrade.

I will add though that there is becoming an ever increasing choice of 27.5 specific frames and if the budget can afford it then the better choice would be one of those. If the budget is tight then this is an upgrade that can be had for about $500 with quality gear, cheaper with budget wheels.

Search the MTBR 27.5 / 650b forums, there is a plethora of info there.

hawkeye's picture

Erm, that came out as a "isn't Crackonfale wonderful" fanboy rant - not what I meant.

What kit said => thumbs up.

Antsonline's picture

I reckon do it.
Those photos are clearly of the 650b 'example' that you cited, so yeah, why not. To be honest, the only clearance issue I would worry about would be proximity of the tyre on the right and left (not at the bridge so much) as it will flex over a bit.
If you are heading somewhere really muddy, then you can always drop in the 26" wheels for monster clearance again.

teeps's picture

I never knew such things were possible!! I can only hope this would be possible for my trek. Sometimes I want a bigger wheel but not all the time. Will have to have a look when I get home.

jbsp1's picture

That's right Ant, the pics I have put up are of a bike that has the 650b's already on. Was thinking the exact same thing about muddy races, just simply switch back to the 26 to allow for build up.
Fork compression with no air also apparently clears with no issues.
The RRs only seem to be available in 2.25. So could always look at another brand of tyre if wanting to go not as bulky due to flex issues etc.

For a small outlay, I think it will be a noticeable difference. Then I have a pick of two bikes really!

kitttheknightrider's picture

I'll check what size my rr are when I get home. They are much wider than the 2.25s I have on my 26er but that might just be because of my wider Pacenti rims. Don't forget you'll lift bb height a bit as well, say about 1/2 an inch, that can be good or bad depending on local trails and personal preference.

Brian's picture

I would convert it. I wish I could convert my RZ140.

russthedog's picture

do your homework first, especially bottom out front and back. It will change geometry, possibly for the worse. Theres a few good articles on the web, check em out

Marvin's picture

this thread has some relevant links

http://forums.mtbr.com/specialized/epic-650b-850...

Cotic Tony's picture

I was looking at having the bigger wheels option for my 26" bike a few months back as it would improve the bikes performance on the longer, flatter stages of say the C to C.

The issues that I found against we're as follows:
The fork manufacturers are all absolutely against bigger wheels being used on their 26" fork citing the possibility of wheel locking up on the underside of the crown when full travel is reached. The outcome of this scenario is pretty obvious.
From the frame manufacturers that gave feedback all said that the geometry has been tuned for a 26" wheel so with only a 3 -4 % improvement in rolling resistance why risk messing the handling up.

That said, many converted bikes are around & the owners are generally rapt with the results.
Fox forks are said to have clearance but not Rockshox unless specifically 27.5/650.
Some converted bike owners also added travel limiting bumpers to prevent the last 10mm of movement being achieved.

Personally I tried the wheels off of a Norco 650b on my Yeti & found the 2.25 Nobby Nics fitted under the Fox arch but rubbed on the rear triangle. On my hardtail both fitted fine. I didn't go any further with the project as I realised that wheels, cassette, tyres etc would still mount up to a fairly high figure & I'd only increase the rubber mountain in the garage even further.
Next buy will be a light 29er duallie.

One other comment of note was from someone who said that their 27.5 isn't getting ridden much as their 29er is still their favorite. They thought that the "mid" option was for the undecided..

kitttheknightrider's picture

I love the way everyone has a "mate" that has an opinion on why people they have never met have done what they have done. Swim past the bait, swim past the bait.

I ride a 'tweener and I have made my decision that I am very happy with. As soon as I can afford to I'll be buying a second set of B wheels to convert my spec enduro.

BTW did I tell you I had a mate that thinks 29ers are for two types of people, those that are so hell bent on getting to the end of the ride as quickly as possible they forget about the journey on the way and those that are afraid of smaller wheels hitting sticks on the trail. Eye-wink

Slowpup's picture

I have a mate that can prove that 'tweener wheels are absolute stick magnets. The 'tweener tyres are also weak and prone to total failure after just three rides. Eye-wink

Using the same set of data collection points 29ers and 26ers are absolutely the only bikes that will get you to the end of a ride!

It is great that there's choice and variety in the world.

kitttheknightrider's picture

slowpup, my mate reckons your mate now knows not to run his non tubeless race day tires at ridiculously low pressures, especially when he is ridiculously over weight.

hawkeye's picture

LOL you guys are the new OldAndSlow and Spokey Dokey double act! Smiling

Cotic Tony's picture

27.5 rims & matching DT DB spokes on the way as my old DT Swiss 4.2's are about one spoke key turn away from pretzel(ing), plus I couldn't resist the challenge any longer.

I am now looking at racing rubber (Which in 650 is a challenge in itself)& will probably end up importing a Schwalbe 2.25 Nic Ralph combi unless my local dealer can get the Rubena Kratos Scylla combi in 2.25.
Discs will be Hope saw lightweight floaters from my other bike & those in turn will be replaced by XT Icetech 180/160 rotors which will match the brakes on said bike.

As I mentioned earlier these wheels are being put on my 26" HT & Yeti duallie with one purpose in mind, to go faster, I'm therefore going low weight & fast treads & as I'll be running identical hubs & rotors I can swap back to any of the the two bikes original wheels in minutes.

Once together & tried out I'll report back on how they go compared to their smaller brothers.

Could be a sucker for new stuff but it will only cost me rims, spokes & a couple of tyres to find out.

T

kitttheknightrider's picture

Tony.

Having also gone from a 26" hardtail to 27.5 hardtail I'd be interested to hear your take on things. The big change for me was I didn't seem to want to be out of the saddle as much.

I'll PM you links for where I got my tyres. If weight is a goal then RR's are your best bet, just watch how low you run the pressures. There is also a place in Brisbane that does a lot of 'tweener stuff, I'll find the link and send you that as well.

hawkeye's picture

@Tony: My beef with the Rubena tyres is they are small for the nominal bag size. 2,25 Rubena = 2,0 or smaller in most other brands.

Unless you have very wide rims or can get the 2.4" (nominal), I'd pass on the Rubenas and stick with the NN/RR combo. The Rubenas roll just as well, but don't hook up as nicely in as wide a range of conditions. They're a lot more condition specific (clean hardpack).

I'd also run the NN's in reverse rotation. I think we discussed this before and you agreed?

Had an interesting conversation with the senior mountain bike guy at Bourke's Bikes in Taree last week when I was in there chasing chainring bolts. He spotted what I'd done straight away and it was interesting to hear him firmly state the view that (in his opinion) Schwalbe had made a mistake and put the arrows on the wrong way!

Cotic Tony's picture

Hi Hawkeye
Yes, we did agree re the Nics. I've run them "wrong" for 5 years now & trust them far more this way, they give more warning that they're breaking away this way. I've had some epic held slides when I'm right on that limit over the last few years.

As I'm sticking the 650s on a 26er I'm actually after a slightly smaller tyre due to clearance. I've found the Rubena's fast & light & also comfortable (high TPI count?) even if they do come up a wee big small. I have also tried 2.25 Schwalbe's which just fit & have also considered Conti's as they also come up a bit small for they're stated size.
I'm also convinced that for me the Snakeskin, Protection, Exo versions running tubeless are the way to go when speed is high on the list . The basic TL ready versions are too delicate & the full USTs are a bit heavy.

Btw, the WA rock finally took its toll on my rear Scylla sidewall, they have a few small sidewall punctures which refuse to seal well enough to run tubeless despite patches. They now reside on my partners bike fitted with tubes as there's about 50% of the tread left.

T

pmbc.crash's picture

I've thought of converting my Mojo HD as well. When I contacted Ibis about it their concerns were about mud clearance and raising the height of the bottom bracket. Since it's only covered under warranty in the 140mm configuration and mine's a 160, I decide against it. I couldn't see the point, since the geometry of the bike was designed around 26 wheels and it's already a great bike.
If you look at the results of the first Enduro World Cup round, you'll find that althought a 650b bike won it, it was only by a small margin and most of the top 10 were on 26 wheels.
My point being if it only makes a small difference with some of the worlds best riders I wonder how big a difference it's going to make to the average punter, especially on a converted bike. It might be huge, I don't know.
Still I would be interested to hear about how it goes.

Nick R's picture

As I recall there was an article in MBA a few months back that did a scientific comparison of 26, 27.5 and 29 wheel sizes and found that there was really very little noticable difference between the 26 and 27.5 wheel size. I think it was something like a few percent performance difference that it would hardly be noticable especially if using smaller tyres on the 27.5 for clearance. I'll look for the article but I also got the impression that 27.5 wasn't halfway between 26 and 29 wheels in terms of performance, it was closer to 26 performance.

Cotic Tony's picture

I agree with what you've put Nick, I'm not expecting much difference either but seen as how I need new rims anyway I thought that I'd give it a go.

My logic is simple: I like the way that my 29er smooths the ride but like the lightweight zip & fast acceleration of my 26" bikes.

Simply fitting huge tyres to my 26er doesn't really work as big (2.4 +) tyres are generally pretty heavy & squirm around on my XC rims, especially if run at lower pressure where they grip & absorb the trail best.

If I run 27.5" I hope to get the bigger diameter feel but not the weight or squirming at 30psi.

will let you know.

T

Cotic Tony's picture

Hi All
I now have the 650b/27.5 wheels built up & fitted on my 09 Yeti ASR SL 26" duallie. I'm happy to say that they fit & have very similar clearance to the pictures of the Specialized at the top of the thread.
I tried to add pics but can only seem to do it on a new thread.

The rubber that I ended up was the Rocket Ron TL front & Rubena Scylla rear, both 2.25.
The front tyre fits my Fox 32 RL fork with about 5 to 8mm arch clearance.
With no pressure in the fork I could, with downward force rub the remote lockout bolt in the lower end of the steerer tube. I therefore removed this & tie wrapped the cable. if I was going to ride more aggressively I would place a 1cm bump stop on the internal shaft but as the fork is a 120 and the wheels are for XC only I'm not going to bother.
The rear has similar clearance but the tyre is noticeably smaller despite having the same stated size. There are no clearance issues within the swingarm arc at all although a bent rim would touch even if only 5mm out.

I look forward to trying the new set up out.

BTW. My hard tail frame allowed heaps of clearance (1cm plus)around the rear wheel & looked great with 650s but there was no way that the front was going to roll without problems under the arch of the Reba fork. I may swap forks around if the Yeti rides well as I have a Fox 32 RLC 100 gathering dust in the loft.

Will report back on the first rides soon.

All the best
T

Discodan's picture

Outstanding, I've been thinking about converting the Superlight which apparently works very well (see below) although I'd need to swap my SIDs out for a fox fork. Mind you I've barely ridden it for months so I should just start there

Cotic Tony's picture

I took the mid wheeled Yeti out this afternoon after a Thai red curry soup (big mistake as it kept repeating on me).
Here are my first impressions:
The bike felt noticeably taller despite only rising approx 1.5cm in height. It also felt less agile. I suspect that the rear end of the Yeti was flexing due to the extra leverage created by the 650s & the lightweight wheel set.
On the plus side when the trail straightened out the light, fast wheels shone, speed picked up quickly & the ride was comfortable,
Oddly, when the trail turned downwards especially on smooth stuff the bike picked up speed noticeably more quickly.

Despite feeling pretty slow with repeating curry hampering my analytical ability & small set up tweaks being needed (gears & saddle) my times around the Kal circuit were good, especially on the less tech stages where they were seconds away from my best ever times.

I'll be honest, for I don't think that the bigger wheels suited the 26" bike. It was faster on the less technical stages but at the cost of the bikes agility & dialled feeling on the other (fun) stuff. Yep, the FUN factor was distinctly lacking.
I don't think that the wheel size is the issue it's just that my bike wasn't designed for them. If your 26" has a low bb & a stiff rear end maybe it'll suit you fine.
In the meantime I'll use these when I'm riding predominantly fire roads etc but will probably stick to the fat 26ers for the hills.

Now the gears & saddle position are sorted maybe I'll go again soon just to confirm.....

Update... I spent a couple of hours this eve replacing the Reba 120's on my Ti Ht with the Fox 120rl's & then put the100rlc's back onto the Yeti.
The thinking behind this is that they can now both take the 650s & the relaxed steering angle on the Yeti will now steepen & hopefully sharpen it up. Initial impression of the sub 10.5kg ht with the 650s is f**k this is quick. I'll have to test it out in the real world.

T

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