Speed Concept crank compatibility question

Peter Wick

The bike originally came with a SRAM Force standard (53/39) crankset - and an 11-23 cassette (wtf??). I switched it to a Rotor crank with a Quarq powermeter this summer and have had nothing but squeaks and damaged bearings and many visits to the LBS to get it figured out. No luck.

So, I'm putting in a new crank and getting a compact or going back to the original crankset and switching out the rear derailleur so I can use a SRAM Wi-Fli cassette (with cogs that go up to a 32 tooth dessert plate).

Any thoughts? Would I have no problem with any of the Shimano or SRAM cranksets? I'd like to get it set up with another Quarg so I'll be contacting Rick about that. I'll either try the Rotor/Quarq on my 2008 Specialized Roubaix frame or sell it if that doesn't work.

Dino Sarti

What drive train is on the bike now? Weird that you are having that trouble. Also, why the dessert plate? Are you planning a lot of crazy climbing? That thing will require a lot spinning. I would recommend a compact crank, SRAM/Quarq, if you must replace and a cassette to match the drive train. Shimano makes a 11/28 that is plenty wide and really low when mated to a compact crank.

On my TT bike I run a Shimano drive train with rotor compact and a Shimano 11/28. Power comes from a Powertap in the rear Zipp 404. This set up will climb well on any course I have been on.

There are some WSM who will be able to give you far more info than my n=1.

Peter Wick

I seem to only want to do very hilly races, plus I live in a section of NJ that has a lot of hills including some crazy steep little buggers (12-18%), some that are impossible to avoid if you want to go anywhere nice. My roadie roots have me storming up hills as a default setting but I've learned that I just cannot do that in a tri if I want to run well. I'm getting better at the steady effort discipline but I don't have the gearing that supports it. At IMLP I found myself really wishing I had a compact crank or a WiFli cassette because to make the climbs I was spiking my power too much. Even with more practice after IMLP I still was doing it at the Hunter Mountain 70.3 on my current set up so it is time for a change even if I wasn't having the BB issues.

I have a 12-27 or 11-28 (depending on what wheel I'm using) cassette and a 53/39 Rotor 3D crankset on the SC. So I have to choose between a compact crankset with a 34x28 top gear or a standard crankset and a WiFli for a top 39x32 gear. Might be easier to go with the compact.

Dino Sarti

I can't speak for everyone, but the compact is HIGHLY favored in the Haus. I live in a really hilly part of SoCal and have a compact on both roadies and the TT.

I am curious to see what Mancona and a few others chime in with....

John Withrow

What type of Bottom Bracket originally came on the bike? (GXP, BB30, BB90?). It sounds like your LBS might have caused an issue when they put in the adapter or when they swapped out the BB, or maybe you were just unlucky and got an originally bad bearing set. New Bottom brackets are relatively cheap and should fix the leaking problems, etc.

You should not have an issue with any crankset on that bike. Quarq uses a SRAM S975 for some of their systems And it comes with a GXP or a BB30. The S975 is nearly identical to the SRAM Force crank that originally came on your bike. If you Getthe GXP version, there is an adapter for just about any BB I. The world that can easily take a GXP BB. This way you can swap it onto your other bikes easily if you want to. If your SC originally came with BB30, then maybe you pick that and keep it simple.

If it were me, I'd sell the Rotor Quarq standard crank on eBay and switch to a Compact. I'd probably go with the GXP S975. A compact crank and an 11-28 is plenty of gearing for anything you will find on a triathlon course or in your training. Hell, you'd even be fine at AmZof with that!

GMAN 19030

Speed Concept BB is BB90.

I run a SRAM S975 Quarq (GXP) with the proper adapter kit and it runs great. That stated, the open bracket nature of the SC BB is hell on bearings as dirt and grime gets in there very easily and grinds the bearings down. I'm on my third set of bearings in 18 months and my bike doesn't get a lot of riding outdoors.

I'm an anti-compact crankset kind of guy but I live in flat-as-a-board Texas so I have no need for compact gearing. I use a 54/39 with an 11-23 cassette.

Peter Wick

Thanks, Bob. I hear ya about the grit in the bearings thing. Your post reminds me of when I lived in Chicago. Will Rogers is said to have remarked that "Illinois is so flat you could sit on your front porch and watch your dog run away... for three whole days." When I moved to northern NJ it was a very humbling experience. I used to have a 46x14 gear on my fixie in Chicagoland.

GMAN 19030

I'm just resigned to the fact I'll need to replace the bearings every six months. It's asinine they wear out that quickly but it's only a $20 part so not that big of a deal. There's one reason to not use the $120 ceramic bearing kit. :-)

Dino Sarti

Interesting dialogue. I some how missed the speed concept part. My Madone 6.7 has a BB90 as well and I run a compact S975/Quarq set-up with out issues once I had the proper adapter. The LBS guys had to confirm with Trek how to install, so you may have an install issue.

mancona

I agree with the others, sounds like an install issue to me as every combo you have mentioned should work just fine with the correct bottom bracket/adapter.

When you switched from the sram crank to the rotor, did you change the bottom bracket?

SRAM GXP use a BB that has a 2mm smaller bearing on one side. Shimano and Rotor have the same size on both sides (22mm i believe).

What ever you crank you decide, just make sure you get the right BB for that crank and a Trek BB90 bottom bracket. Since you have had issues I would recommend you take it to a good shop and let them put the new BB in. Once the BB is in, you can easy take the crank out yourself, but the BB install can be tough in some cases.

Peter Wick

Actually, all the work has been done by our local shop. They're supposed to be good. Sigh.

John Withrow

Peter-- Where are you in NJ? I happen to believe that my LBS has the best bike mechanics in the whole wide world, and they are located in Stirling, NJ http://highgearcyclery.com/ and they are a big Trek Dealer. They actually "made" me a bottom bracket for my new P5 by taking a couple different ones apart and using different BB Bearings on either side to create something that would allow my GXP SRAM S975 SRM to work. If you want to take it there to get a second opinion, let me know and I'll talk to the mechanics so you get the extra special white glove treatment.

Peter Wick

Uh, I hate to say it but I go to High Gear in Millburn... They sponsor the Mapso tri club.
Maybe it's worth it to drive out to Stirling?

John Withrow

They have totally different mechanics. Jim Vreeland and Eric Paulsen are the mechanics in Stirling and they really are amazing. But might be hard to "cheat" on your mechanics with the mechanics of their "sister" shop. I think Rone owns both of them, but the rest of the employees basically stay put in their own locations. I'm not saying anything bad about the Millburn location, simply singing the praises of my guys in Stirling. I'd be happy to take it in there for you if you want to stay "clean"... But I'm pretty sure they'll see the High Gear sticker on it unless you took it off already.

I've ridden with some of the Mapso guys in the NJ Gran Fondo last yr, and always see them in local triathlons and sometimes while out riding. Are you buddies with J.T. Thompson who is here in EN? Welcome to da Haus!

Peter Wick

Yes, JT and I were the Mapso collarbone twins last year. He did his at NJ Gran Fondo and I did mine on a mtb ride in Michigan in early November. I did NJ Medio Fondo this year because I was getting ready for the HITS Hunter Mtn 70.3 a couple weeks later. I did pretty good on the Medio route, 2nd overall. Mapso took second to Hilltop in the Gran Fondo team competition.

The Trek SC was actually bought at Marty's in Motown. That was before I joined Mapso. Luke is the poor soul who has been plagued by my bike this summer in the Millburn shop. They do take good care of me there, except that damn SC is a pain in the butt.