Rigid fork and 29er wheels on 26er frame - Advice please

skinz1990

Hi guys,

Im looking to strip down my 2009 Carrera Fury hardtail, powder coat the frame, fit some xc 29er/700c CX wheels and some carbon rigid forks.

Im looking to make it into a light weight, commuter/gravel bike. it wont really be used for proper off road or trails as such. just looking to mess around and make something different with my spare frame. Want it look a bit like one of these -

http://singletrackworld.com/forum/topic/lightweight-rigid-forks-frame
http://singletrackworld.com/forum/topic/fancy-a-rigid-26-or-29

Firstly, is it okay to stick 29er/700c wheels with no bigger than 35c cx tyres on the 26er frame? At the moment It has 26 wheels with HUGE 2.4 Schwalbe Big Betty's on it with a bit of room to spare, so i guessed the 29er/700c wheels will be a similar size overall. Is this correct?

Next thing I need advice on is what size carbon form to go for - 26er, 650B, 29er? Not sure what axle to crown length to go for. Dont want the front end to be too high, want it kind of a cross between a MTB and a Hybrid/Road bike feel.

The fork will probs be one of these -
http://www.on-one.co.uk/i/q/FOMK35CF/mkm-35-rigid-carbon-mtb-fork
The A-C measurement for the 26er is 450mm and 29er is 490mm. Which size would be best for 29er/700c with relatively skinny (35c max) tyres.

So much confusion in the biking world it gives me a headache!!!

Any advice much appreciated. Sorry if any of this is stupid or has been asked before.

Cheers

skinz1990

Thanks for that info, will get the tape measure out to tmoro! Cheers

The Rookie

Cyd is wrong of course, if you keep the same A2C the bigger radius wheel will lift the front end and slacken the geometry (obvious I thought), you want to shorten the A2C from the current (sagged) length by about 20mm to accommodate the smaller wheel/tyre and keep Geo similar, noting that the same frame was also sold with 100mm forks (Vulcan and Kraken) so you can go 20mm shorter than that as well and still keep sensible geo. For the use you want you don't want it slack but fairly steep (compared to an MTB) anyway.

Yes it will all work, a chap I ride with has 2 home brewed 69ers using 26er frames, both rigid, one is his hack bike and the other his light duty MTB.

My Commuter uses a Mosso fork which is ideal for the use you describe, as light as many carbon forks and you can get them new off the Evilbay for sub £50, available in a range of A2C's.

skinz1990

Oh I see. I dont want the front end too high as i want its going to be for the road mainly anyway. Il look into those Mosso forks then. Cheers.

cooldad

But bigger wheels at the back will raise that as well, so even things out.

skinz1990

The mosso forks look okay but not so keen on all the stickers. like the look of these but who knows what bthe quality would be... Any ideas anyone?

http://www.ebay.co.uk/itm/JAVA-26-27-5-3K-Half-Carbon-Alloy-Fiber-Fork-MTB-Rigid-Fork-Disc-Brake-28-6mm-/281797986204?var=&hash=item419c78079c:m:mDtBFMxSLvihTL1_HsnlonQ

The Rookie

cooldad wrote:

But bigger wheels at the back will raise that as well, so even things out.

He won't be fitting bigger wheels at the back, the frame would get in the way!

cooldad

Really? That seems to be the intention.

skinz1990 wrote:

Hi guys,

Firstly, is it okay to stick 29er/700c wheels with no bigger than 35c cx tyres on the 26er frame? At the moment It has 26 wheels with HUGE 2.4 Schwalbe Big Betty's on it with a bit of room to spare, so i guessed the 29er/700c wheels will be a similar size overall. Is this correct?


Cheers

skinz1990

To clear things up guys I DO want to put bigger wheels front and back. I currently have 26inch wheels with massive 2.4 chunky tyures on. Im gonna change to 29er wheels with smallish CX tyres on (35c max) so overall the wheel/tyre combo will be roughly the same size as what im running now.

The Rookie

Sorry, thought you were talking of a 69er.

In that case, yes the rear wheel will fit and yes you need to keep the same A2C fork (within reason) as the current item when sagged.

skinz1990

69er???

cooldad

26 rear and 29 front.

cooldad

Not to be confused with the smutty sites you visit.

The Rookie

A quick desktop calc suggests a 35x700c will have about a 6-7mm larger radius than a 2.4x26"......

skinz1990

Thanks for the help guys.

Measured my current forks and the A-C is 510mm as far as I can see. So would 450mm or 490mm A-C in a rigid fork be best...

God this is hard work haha!

Anyone got any experience with cheap chinese carbon fork off ebay? Theres LOADS of forks but dont know if they should be avoided.

The Rookie

skinz1990 wrote:

Measured my current forks and the A-C is 510mm as far as I can see. So would 450mm or 490mm A-C in a rigid fork be best...

Is that sagged or unsagged (I'll assume sagged)?

Sagged the A to C will be about 480, if your frame had the 100mm forks used on the lower models it would be about 460mm.

For a rigid MTB use I'd say 490, for a road/gravel track use like you intend I'd steepen up and go with the 450mm.

Cyd - happy to admit when I get it wrong....

skinz1990

I ended up pulling the trigger on some eXotic carbon forks with A-C 445mm so hopefully they should be okay for my intended use... :?

That 510mm measurement was UN-sagged with 120mm fork.

Now enough with that techy stuff...

Does anyone know what the finish looks like on an alloy frame thats been shot blasted and nothing else? Quite like the look of raw titanium frames like the On One Pickenflick, but not sure what raw alloy would look like after blasting. Does in need any special finishing/polishing, etc? If it would look crap I will probs just end up painting it glossy white, cant go wrong with white.

Monty Dog

Raw alloy will oxidize so the finish will be pretty dull unless you polish it and put some sort of protective coating over it. If you want durable, go for powdercoat. Most titanium frames are vapour blasted - some are polished but it's less common. Trouble with any polished finish is it shows up fingerprints / greasy marks etc.

The Rookie

You won't be shot blasting an alloy frame unless you want to throw it away afterwards, you may mean soda blasting?

Soda blasting will bring it up as a fairly shines finish, polish with wire wool and then use a car polish and it will stay that way, a friend has a frame to which he did just that and it still looks good three years later.