Buying Exotic Carbon forks / MTB singlespeed conversion

lawson_m20

Hi there,

I'm just about to start my converting my Stumpie M2 (about 10 years old?) that I commute on to a rigid singlespeed (I have the disc wheels and 2nd hand Avid Juicy 3 F + R brakes that I bought on the forum) and I'm considering these http://www.carboncycles.cc/?p=195& for the front end.

My queries are:

* Have I got the correct forks for the geometry of the bike (the original forks are Manitou Pro with elastomers)
* Is the steerer on my Stumpie 1 1/8 inch?

Any help/advice appreciated.

Cheers, JM

hoathy

yes and yes.

good call on the rigid single speed. are you going to go for a conversion kit or a proper single speed rear hub?

lawson_m20

Thanks for the quick response. I would also ride it on some forest tracks with the kids.

I was thinking about a conversion kit like those @ On-one. Do you have any better suggestions?

hoathy

chainreaction will build you a rear wheel to your chosen spec with a DMR Revolver Single Speed hub, the wheel isn't dished, so it is stronger, and it makes a much tidyer job of the whole thing. You will still need a chain tensioner though; you can get one pretty cheap, mine is a gusset one and its fine.

do you have tyres? have you thought about gearing?

lawson_m20

Thing is, I've manage to help justify this job because I got some free disc wheels off a guy on the forum and they are hanging up i the garage at the moment.... I might not get away with a new wheel as well as the forks that I really need to run the disc brakes to keep me safe when it's raining (My v-brakes were frightingly rubbish in tonight's rain). Hence a conversion kit.

Mmmmm.... haven't really thought about gearing properly... For the last fortnight I've been running on my middle ring (32 teeth-ish) and the smallest gear on the back and that has been ok for my commute and extended commute.

I've already got some slicks (can't remember which ones, but they are fine.

supersonic

425mm will contemplate the original geometry.

nicklouse

supersonic wrote:

425mm will contemplate the original geometry.

been on the Beer Paul?

compliment might be a better word!

To consider carefully and at length; meditate on or ponder.

supersonic

Hehe, we must think these things through... ;-)

hoathy

Sounds good. You can get disc compatible DMR revolver hubs, but if you already have wheels, then thats always a winner.

Be careful using your current middle ring, it will be ramped to help you shift gears, but this means it will throw the chain more easily on a single speed set up. It might be worth investing in a single speed specific ring, they aren't too expensive, and it'll be worth it.

bomberesque

Generally; great idea, a new lease of life for an old but quality frame. Minimal (I stop short of saying non-existent, but just about) maintenance and you get to laugh at your mates in the rear view when they can't catch you on hills (ok, this may or may not happen, that depends on you, and to an extent on your mates)

Chainring; Hoathy has a point; SS specific ring is better but if you set the the chainline up right, you shouldn't have a problem with shipping chains. I'd run it as is until the chainring wears out and then get a SS one but there you go
Wheels; you have yours so that's solved but for the record, I like converted wheels better than SS specific ones. On paper the strength argument is a good and logical one but in reality, I've only broken a wheel in the last 10 years crashing. Plus pricing on "normal" 9sp hubbed wheels is a *lot* keener than on ss specific ones.
Chain tensioner; I don't get on with the sprung ones, they bob like a deurallier (even a bit) which the fixed ones don't, one of the great things about a SS setup is getting rid of the slack chain and the bouncing that comes with. I got a DMR kit from CRC, about 30 quid included the 16T sprocket, tensioner and spacers to get the chainline just so. Simple but effective.
Fork; Unless you really need to lose the extra 200gr, I'd go with something like the surly 1x1 fork instead of the Exotic. Cheaper and *tons* stiffer. I had the Nukeproof carbon fork (almost exactly the same as all the other straight legged carbon forks, they're all from the same factory iirc) and they didn't track very well at all. if you put a post up in classifieds, you may even get a bargain on a 1x1 fork, as the Surly 1x1 frame cones with one included and people often swap them out for a sus fork.
/edit; Ratios; Have a think about this. 32:16 is the "classic" SS ratio but it's meant for offroad. On the road you'll find it too spinny, topping out at about 25kph. All conversion kits that I know of come with 16T sprockets so that's where to start, you can always gt a different one later, swap out the chainring for a 36T or there is the "dinglespeed" set up where you have 2 sprockets and 2 chainrings selected so the teeth count on each combination is the same, then you can have an offroad ratio (32:16) and a road one (36:12), chainlength remains almost exactly the same so you can swap it at the side of the road. I never bothered with this though (spinning 5 km to the trails is a good warm up for my legs), just an idea.

oops my 2p ran out....

supersonic

Here is a radical idea - use gears?! Say a single 48t chainring with a 11-34 cassette.

bomberesque

supersonic wrote:

Here is a radical idea - use gears?!.

pfft. crazy talk that

hoathy

don't agree about wheels, if i had the choice, and i did, i'd have a SS specific, they aren't more expensive.

I used to run an on one carbon fork and it was great and really light.

lawson_m20

Thanks Guys.

I've had a quick browse on here and other sites, and the Surly forks sound like they will do me fine. They are £55 at Wiggle at the moment so are also a few quid cheaper than the exotics.

bomberesque - how easy is it to take the rear wheel off when there is a fixed tensioner like the DMR kit you have suggested? I will need to take mine off a couple of times a week to put the bike in the car.

I'll invest in a new chainring and rear sprocket.....probably 36:12, the "dinglespeed" sounds like a good idea, but initially most of my cycling will be on the road (I got one of these over the summer: http://www.bikeradar.com/gear/category/ ... 0-09-34565 and am still gettting used to it).

Cheers, lawson.

Salsa

I wouldn't go 36/12 as it's way too high a gear, running it through Sheldon Browns gear calculator it comes out as 78 gear inches. I run 44/16 on my commuting/shopping bike & that's slightly over geared but comes out at 71.5 gear inches.
It's easy enough to remove the wheel with the DMR tensioner, just undo the bolt that locks the tensioners angle & remove the wheel, put the wheel back in, push it against the chain & tighten the bolt again.

It's worth starting with the DMR style 16 tooth as it's teeth are deeper than on a cassette & grip the chain better. An un-ramped/un-pinned chainring is also a good idea for the same reason.

hoathy

Salsa wrote:

I wouldn't go 36/12 as it's way too high a gear, running it through Sheldon Browns gear calculator it comes out as 78 gear inches. I run 44/16 on my commuting/shopping bike & that's slightly over geared but comes out at 71.5 gear inches.
It's easy enough to remove the wheel with the DMR tensioner, just undo the bolt that locks the tensioners angle & remove the wheel, put the wheel back in, push it against the chain & tighten the bolt again.

It's worth starting with the DMR style 16 tooth as it's teeth are deeper than on a cassette & grip the chain better. An un-ramped/un-pinned chainring is also a good idea for the same reason.

i agree with all of this. and remember that when you drop the rear wheel out of a single speed you will end up with the chain coming off the front ring so you'll have to put it on each time! If there is one piece of advice i'd give it'd be use non-ramped rings back and front: http://www.chainreactioncycles.com/Mode ... delID=3334

Salsa

Yep those non ramped chain rings are worth it & not a lot of money. I was lucky as I managed to pick up a less used BCD Salsa non ramped chain ring (5 Bolt 94mm BCD) for £5 from a shop that had ordered it in error for a customer & couldn't sell it. I had previously changed a crank set for someone & kept his old CODA crank which fitted this ring.
It wasn't the exact size I wanted but it seems to have worked out for me, SPDs help on single speeds a lot as well imo.