DH - single speed conversion

I think I'm done with rear derailleurs on my park bike. I'm debating switching to a single-speed with a chain tensioner.

For those that have done it;
- Do you really need a single-speed conversion kit or can you just leave your cassette in place and use one of the sprockets? i.e. is the conversion kit a must-have?
- With the conversion kit, since it only uses a single sprocket, do you see faster wear on the hub body?
- Chain tensioner - sounds like the Shimano Alfine is the one folks use on DH bikes - how do you set the chain length? Same as with a derailleur?

It looks like the conversion will cost ~$75 - considering I went though one derailleur and a shifter this year (over 5 days in the BP…and yeah they were at end of life), this seems attractive.

Any experience/insights?

-Gord

Add-on question out of curiosity, anyone know the approx. weight savings going to single speed from say Saint shifter/mech/11-26 mid range casette?

Nothing eh? I must admit I'm surprised.

I could be totally wrong but I don't think a tensioner will have the ability to handle the dynamic changes that happen to a full-sus bike in a park. Maybe but they don't tend to have a large range of motion to handle expansion and contraction.

I've done a conversion kit on a Stiffee, it works well enough.

I just toss old gear from the trail bike on the dh bike. Gives me an excuse to upgrade the trailbike and I don't care about shift quality much on the DH - don't even shift that often really.

Zerode G2
/thread

http://www.sicklines.com/reviews/yess-pro-vertical-full-suspension/
Made in canada, best tensioners I've ever used.
Not sure if they're still in production.

sorry, didn't see the other Qs.
Dedicated SS sprocket is a must. you can use old cassette spacers to make up the width on the hub.
If your hub has a steel carrier then a normal width SS sprocket is fine.
If alloy, you're better off with a wide base SS sprocket.
good chainline is important. take your time.

Shifter pod 150g, rear meck 250g, dh cassette 250g, plus a bit for the tensioner, you'll Prolly drop 5-600g total.

great info, thanks revanche.

Looks like Yess are out of business, so I will likely head the "Shimano Alfine Tensioner" route.

with an aluminum XT hub body, I'll look for a wider sprocket - thanks for the advice.

Looks like Yess are out of business, so I will likely head the "Shimano Alfine Tensioner" route.

I know it's heavier, but for aggressive use your best bet for a tensioner is a Shimano rear derailleur with a clutch.

Change out the set screws as necessary to adjust chainline.

I've used Paul's (really nice) Melvin tensioner, YESS, Alfine, and a couple others in various experimentations with full sus single speeds and nothing I've used compares.

Run the chain as short as possible to accommodate chain growth through the full travel (remove spring or let air out to test for longest point).

You don't have to worry about shifter feel so you can crank up the clutch a bit as well.

Are you seriously destroying decent spec shifters and derailleurs within 5 days of bike park riding?? I hate derailleurs as much as the next guy, but I gotta admit that the high end stuff is pretty bombproof these days. Are you breaking them in crashes, or JRA? What bike? What brand derailleur? Just curious - I know that some bikes tend to be really hard on derailleurs.

Hi Ryan,

2007 Kona Stinky which I've kept alive and been upgrading over the years. Essentially the frame is all that's still stock.

The latest derailleur was an SLX. In one day I managed to snap a cable, lose the top jockey wheel twice and bend the wheel cage. I hauled the derailleur off last year aswell. Last year on Velvet, This year on Frieght Train, so I wasn't threading the needle on techy stuff.

I'm more interested in simplicity and considering that I don't shift much in the park, single seems like a cleaner option.

Yeah, not too surprised to hear of an SLX blowing up - not really made for bike park duty. To be honest, I haven't used a Shimano derailleur in years. I just recently unloaded a 4-year-old, 9-speed X0 that should have died in its first year the way I was treating it. I can't believe the abuse that thing endured. The thing was a bit bent and had pivot play when I got rid of it, but it still shifted ok. I currently have an X01 7-speed on my DH bike, and it's burly - you can tell just by holding it in your hand.

Long story short - you truly do get what you pay for when it comes to derailleurs. Not trying to convince you to abandon your single speed idea, just my two cents.

I totally agree with respect to $ vs value for derailleurs. For a bike that I ride [HTML_REMOVED]5 times per year…and that I'm nursing along year to year, its tough to justify a larger expense.

Heck, maybe I'm just cheap.

In my mind, something is attractive about the simplicity of a single speed setup. At this point, I'm buying a tensioner or a new derailleur anyway, so I may as well try the single-route and see how it goes.