I don’t know anything about your existing FSA crank, but can you sell that and get a bit more back?
no idea. Guess so.
Don’t know how much it’s been used, but it’s a few years old.
Another plus is this keeps everything consistent between bikes, so you can have good confidence the power readings are consistent and you have spares readily available should you need them in a hurry.
1 Like
Might be worth checking your BB first in case you need an adaptor at additional cost.
Apologies if he’s replied but @leahnp has a Giant TT bike (well I think it was but he left me for dead 
)
Possibly other options like Giant’s own, the one on my Propel seems good. I’ve got 2 SRM’s that hardly get used, the problem is they cost something like £150 for a service and battery change! And I’m expecting one to go at some point.
Yeha I text my bike shop mate. He’s gonna look into it.
He thinks one of his suppliers may be a 4iiii distributor as well, so there maybe a discount to be had.
I just bought a 105 7000 4iiii crank off Facebook for £100 
1 Like
As others have said, this is a rebadged power2max, so I’d endorse this.
One thing I would say is that with this option you’re getting full power, rather than 2x left. I’d argue, especially for long distance tri, you want to be as precise as possible. The value is in guiding your pacing, and 10-20w can make a big difference. That’s only a 5-10w difference due to imbalance when left only.
Over longer durations, you also have the risk of any imbalance changing over time. So if you’re 50/50 when fresh at race pace, but your left leg fatigues quicker meaning you’re 45/55 after 2hrs, hitting a 200w target on your bike computer will actually mean you’re doing 222w. So right at the point you want the power meter to help guide your effort, you’re actually digging yourself into a hole. Or conversely, you’re leaving power on the table.
Ultimately this is just the standard drawback of single sided, but for a steady state TT race bike, I think there’s something to be said for maximising the accuracy of the numbers it’s producing.
2 Likes
Thanks @stenard
1 Like
Ok i’m pretty tempted by this now.
So, a few options. What’s the real life difference between a 172.5 and a 175 crank? Is there a body type that suits one or the other more?
Secondly, gearing options. I’m weak, so i guess 50 x 34 would be the best bet, giving me options for hillier stuff (locally and future races).
172.5 vs 175 - you won’t even be able to tell the difference, if going down to 165 or the like for a TT bike I can see the point but 2.5mm is neither here nor there.
I like 52/36 as a “best of both worlds” kind of set up, combined with a decent sized cassette on the back you’ve got low enough gears to get up almost anything and still decently high ones for descending. The trade off is some slightly larger jumps between gears but they’re mainly between the lowest gears when you’re usually grateful for it anyway (well at least I am)
1 Like
Similar to @JaRok2300, I’d go for 52/36 as a nice compromise for high and low gears. I’ve ridden that with a 28t on the back basically everywhere on the TT. I used it for the climbing at Mallorca 70.3, although did stick a 32t on the back for the full just to make things a little less heavy on the legs.
Depending on if you’re going 4 or 5 bolt, then 5 bolt probably means 110bcd to be able to run the range of rings you’d want. 130bcd is fixing you at 53/39 or higher I believe. Newer 4 bolt (which is also 110bcd I think) is more versatile and I think can take all of them.
I agree you’d not notice any real difference, but unlike a road bike, most people would lean towards shorter cranks on a TT bike. It keeps your hip angle slightly more open at the top of the pedal stroke. I have 172.5 on my road bikes, but 170 on my TT (largely because the more extreme short cranks are harder to obtain).
Every 2.5mm makes a 5mm difference in how much higher your foot is going to travel (the bottom of the stroke is fixed in space relative to the saddle), so it can quite quickly make a more noticeable difference to hip angles (although I’d agree you’d almost certainly never notice it in terms of just your pedalling when sat upright)
3 Likes
Thanks both.
1 Like
Just added a bit extra on bcd in case that’s of relevance
Don’t even know what that means, but I will look into it. Ta.
Longer cranks normally help with your max sprint watts.
Bolt Circle Diameter
Older cranks had the bolts further apart, couldn’t get a chainring smaller than 53 in. Lots of new cranks are 110 which means you can get a 50 and sometimes smaller chainring in. Just gives you more options.
1 Like
Another one for 52/36, you can get a bigger cassette at the back if really necessary.
I’ve got 165mm cranks on the TT bike after a recommendation but hardly had the chance to ride\race it since so no really feedback, except they are difficult to get hold of. The people who like it will swear it makes them faster.
Stenard’s comments about opening the hip is usual benefit, there seems to be a bit of logic behind it and I think Wiggin’s used them in his hour record?
1 Like
Thanks but… Doesn’t the BCD limit the size of the smaller chainring rather than the larger? Pretty sure the 50/34 compact on road bike is 130BCD.
In that case, does anyone sell 200mm cranks for Zwifting?
3 Likes
50/34 is 110bcd on older 5 bolt.
A quick Google suggests the smallest ring on 130bcd is 38t