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Single speed conversion Advice


ChopStiR's picture

By ChopStiR - Posted on 06 January 2012

I thought I would have a crack at converting my old 2002 Giant Yukon to single speed.

It has just dawned on me that I may have to get a new crank set.
Ive never pulled it apart and I dont even know what the Bottom Bracket looks like.

I found the Archive specs for the 2002 Yukon.

The Crank is a Shimano Acera, after doing some research I think my bottom Bracket is a JIS square taper 68mm.
Can I do a single speed conversion with this?

If I do need a new crank, what do you think of this Brown Jersey Crank? Australian Based, Im assuming I would need to change the chainring.

Any Recomendations on Convertion kits, tensioners?
What teeth would you recommend a slow rider?

With this Shimano Tensioner, could you run a 3 speed bike?

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jaseh's picture

I just bought a set of raceface ride SS cranks from crc for about $120. They also come with a botttom bracket.
Just use a dmr sts tensioner they come with the 16t sprocket and the spacers to fit it on a 9sp hub and are cheap and work well. 32/16 is a good ratio to start with. Those cranks look like they would be suitable on a fixie road bike with that 46t chainring.

moggio's picture

I'd keep an eye out for second hand cranks on Rotorburn... can usually pick up a set like SLX for around $100 with a BB.

You use the middle ring and just get bmx chainring bolts which are shorter to attached the one ring.

For tensioners I will avoid the roller types like the DMR, they just don't have the pressure if you put in a lot of effort up a steep hill.

I like these sort of tensioners best

http://www.ebay.com.au/itm/Diamondback-Bike-Cycl...

but I do a few mods on them.

For spacers either get a kit of ebay or cut some PVC if you want to ghetto.

Also you need a heavy duty chain. Get a BMX chain so you know it won't snap.. the little extra weight is worth the piece of mind on the steep hills.

For gearing I use 32:17 in the mountains because of the hills... 32:16 is great when you don't have any real nasty climbs. If its going to be more on the flat go 32:15.

DigDig's picture

jenson still has lx cranks with bb[68/73 mm shell]new for 89.

ChopStiR's picture

Cheers Guys

That LX does look like a good buy.

I found a bloke on rotorburn selling a Shimano SLX Chainset 10 Speed M660 Brand New still in box for $130
AUD$171.79 CRC
AUD$127.18 Jenson
If this will work I think I will try and keep my money in Australia. To much money goes overseas.

Purchased so far

From Torpedo7
DMR Single Speed Kit 16T $19.99
TORPEDO7 Single Speed SprungTensioner $11.99
(PUCCI T-Handle Scale - 55lb / 25kg $14.99 Thought I would add it to the postage so i can weigh my bikes)
p&h $9
Sub Total=$40.98 does not incled the scales

From Wiggle
Avid Speed Dial 7 Brake Levers $32.32 AUD That includes p&h I wont need the Shimano Brake & Lever combos

Total So Far = $73.30

All that is left is the crank, 32T ring and BMX Chain. Hmmm....May need some tools
What tools may I need? removal of current crank, installing new crank, changing of cassette for SS,...
Are BMX chains a standard width?

Would love to get a set of these later on. Not Cheep
Avid Single Digit Ultimate Brake AUD$109.43 each

DigDig's picture
moggio's picture

Nah Wes, I have experience with those tensioners. It is a great price but I think they are fine for DJers and the like but for XC they just don't hold the tension and slip badly. If you have almost a perfect chainlength they will be ok, but if any amount of tension is required, once you hit the hills they slip and send you over the bars.

The one Tim got is actually really good and can add a lot of tension which allows for changing between say a 16T and 17T. I used to use one of these with the moving section from a Surley Singulator which is better for that part but I found their spring not quite strong enough. You can also hook the spring around the tensioner frame which adds just a little more tension as well.

As far as a chain goes get a good one... I use a KMC one that has been used and abused for a few years now chopping sticks, rain, mud etc and it has never had a bad link. Find a halflink connector as well so that you can get your chain almost correct in length. (You can buy a half-link chain but they weigh a lot).

You can use just your 32T ring from a set of cranks, a DH type ring ranges from around $50 to $90.

Tools you need the shimano crank tool and the cassette removal tool and a chainwhip which you can make yourself and looks kind of like a scary weapon in your bike tool kit. Smiling

Muninjitsu's picture

Tim i use the singulator that you have bought on my SS and have not had a problem. I also use a sram 9speed chain which has served me well.

ChopStiR's picture

Here is a progress photo.

http://i1000.photobucket.com/albums/af128/chopst...

Ive been held up as I need more tools and funds. Xmas break is not good for a casual.

I need:
32mm spanner to use with the Bottom Bracket tool.
Hollow Tech Wrench to install the new Bottom Bracket.
Star Wrench keys to remove the 2 uneeded chainrings.

I would also Like to get myself a Carbocage Chainring

ChopStiR's picture

Cheers JP for the loan of tools.

I have now stripped the old and uneeded parts from the yukon (Pictured link below).
I was quite suprised by the large weight difference in hand of the new and old Bottom Brackets.

I have now ran into another stump of progress. The chainring nuts are to big for the middle chainring alone.
So I will now need to get some small chainring Nut and bolts to progress. Im thinking I will just get the chainring I wanted which comes with the smaller nuts and bolts.

Good news is this should be the last challange aside from lining the chain up.

http://i1000.photobucket.com/albums/af128/chopst...

moggio's picture

The shorter bolts are BMX type or track bikes. You can also use little spacers which come with the MRP 1.x.. I have a few of them lying around if you can't find any short bolts.

The Brown Hornet's picture

I have shorter bolts mate. I'll scrounge them up today and let you know.

Username2's picture

For a fix i have filed the bigger bolts down to the requird size, can be a little lime consuming but it makes for a cheap fix!

ChopStiR's picture

Ready to ride

The chain ring I ordered apperas to have dissappeared in the mail, so JP has come through with the goods loaning me some shorter chainring screws. Big thanks to others who have offered to help me along the way.

I had a liitle difficulty on the first test run with the chain slipping although I wasnt sure what was happening at the time. Wanting it ready for tomorrow I ducked out to the LBS with the bike for some professional advise. They suggested removing another chain link. They ended up just doing it for me on the spot which saved me some trouble and now it is working great. The BMORC Bash on the Oaks tomorrow will be a good test.

I had weighed the bike before changes and after changes and it has lost almost 2kg in weight

Enjoy the bike porn, I cant wait to give it a thrashing! Laughing out loud
http://i1000.photobucket.com/albums/af128/chopst...

http://i1000.photobucket.com/albums/af128/chopst...

P.S. The SS may be up and running but this isnt over!!! More changes to come in the near future Eye-wink

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