FMurray

Hi there,

Looking into purchasing a Power Meter for my road bike in the near future. Looking towards lower end of the market, so crank power meter. Specifically been looking at the 4iiii precision power meter.

My road bike is currently fitted with a FSA Gossamer bb30 crankset.

Looking for some guidance. Take it I couldn't keep the crankset and fit the 4iiii power meter as left crank? Would I need to swap out the FSA crankset for shimano 105 to fit that specific power meter? Anyone got any other suggestions?

Help a road bike newbie out!

Cheers

unterhausen

I don't know that much about FSA cranks. On Shimano, you can swap crank arms between 105, CX, Ultegra and dura ace. Not sure if there is a similar situation with FSA

I'm a little upset they didn't name their precision model "Preciiiision" like they did with the Podiiiium model.

John_V 

If for some reason or another, you have to replace your bike and want to transfer your power meter to it, you're going to be stuck buying a bike with a BB 30 bottom bracket. From what I'm seeing, many of the newer bikes are getting away from BB30 bottom brackets so future buying selections may not be very good. Pedal based power meters will move from bike to bike regardless of the bottom bracket. You may want to save up a little more money and go pedal based.

adamrice 

I don't think that's right. A 2-piece crank that is compatible with BB30 should also be compatible with BSA.

John_V 

As long as the spindle sizes are the same. A BB 30 uses a 30mm diameter crank. Shimano uses 24 mm spindle and SRAM uses a 24/22 mm tapered spindle. Others like Praxis, I think, use a proprietary size spindle. So using a crank based power meter that is made for a BB30 can be transferred to another bike as long as the BB accepts a 30mm crank.

DrIsotope

Nope. BB386/392 & BBRIGHT will fit in BSA30. The spindle on a BB30 crank is way too short to fit anything with external bearings.

The upside here is that there are pressfit BBs to adapt the frame to pretty much any crank.

4iiii 105 PM ($300) + Shimano R7000 crankset ($160) + Wheels Mfg. BB30 to Hollowtech ($85) = $545
power2max FSA Gossamer NGeco BB386EVO ($540,) will fit current BB with outboard spacers.

Both options have some future-proofing built in, as the spindle lengths will fit most any frame, and can then be transferred to a future bike.

Seattle Forrest

This is very good stuff to be aware of when choosing a PM. I went with pedals for this reason (and because a hub based meter limits you to brake type). DrIsotope did well with a p2m that would also have worked for me.

Power makes as much sense on gravel as anywhere else, and road pedals and cleats are workable, but sometimes they're difficult and annoying to use.

srode1

There are BB adapters that will let you change from BB30 to Shimano 24 if you want to get a crank based PM that is Shimano size based. Another option is using pedal based power meters which will move to any bike / crank / BB you have. Garmin Vector3 as an example.

John_V 

I just woke up a while ago and it may be that I'm still partly asleep but how do you manage to adapt a 30mm diameter spindle down to fit a 24mm ID BB bearing?

srode1

You're right, that would work and perhaps I should have been more clear - if he used a 24mm Shimano Adapter on his current bike with BB30 BB, and bought a 24mm Shimano crank based power meter, he could use it on that or any other bike with either a shimano BB or with an adapter to go to 24mm on that second bike if needed, and then he could move the crank between any 2 bikes easily. There was a comment about him not using a Shimano crank earlier because of compatibility with his BB I probably should have referenced.