170mm vs. 165mm
 

I bought a set of 170mm crank arms, but am kinda worried about pedal strike. They will go on a eighthinch scrambler v2 frame. Is my concern legitimate (should I send them back and exchange them) or is 5mm not enough to worry about?

5 mm will make the difference between scratching the pedal and twisting your ankle flipping over bars and breaking a clavicle.

I have 172.5 cranks on a road frame with a lower bottom bracket and never EVER get pedal strike. I can't even remember the last time my pedals scraped, even when I'm thinking how far I'm leaning over and not getting pedal strike. Get some pedals with a narrower Q factor if you're really worried.

It might possibly be an issue one day. Maybe. Unless you've had trouble with pedal strike before, or happen to like huge BMX platform pedals, or have some other extenuating circumstance, the 170mm should be just fine. It's not worth giving up the days riding for those 5mm.

At a standstill, see how far to the side you can lean a bike before you strike a pedal, it's pretty incredible actually.

Pedal strike with fixed riding is an area of deserved paranoia. I doubt word will sooth your concern. I suggest finding an empty parking lot and go about finding out how far you have to lean the bike over before you scrape a pedal. Roll the bike over in small increments and the the first time you whack a pedal should be a minor ordeal. I think you'll be surprised exactly how far over you will be able to go. Plus, you'll have an absolute feel for where that break point is on your bike with your setup.

you will only have to worry about it if you take the sharpest corners ever'
in which case you provbably wont'
because i have 165mm cranks
and took a sharp turn
ended up eating ****
and liek you don't have to worry
unless you're going really sideways and whatnot

You don't even know his BB height or what kind of pedals he's running.

OP: 170mm should be fine. I've got stumpy legs and 165mm cranks feel better to me than 170mm, but even with my old cranks pedal strike happened so infrequently as to be essentially a non-issue.

170's are just fine, unless of course you're planning to hit up the Velo daily. I ride 170's on the road instead of 165's due to the fact that I'd rather have that extra little bit of torque when I turn my cranks.

If you had some REALLY low BB height and had 175's, I would get worried, but you have no problemo :thumb:

Put the 170s on your bike. Put pedals on 'em, then lean the bike over and see how far you'd have to lean to strike.

Chances are, you'll rarely lean that far over.

Even on my road bike, with a low BB, I can pedal through most corners - in races, at 30 - 34mph. I don't always do it, because I *have* pedal struck before and it's a bit unnerving to have your rear wheel lift up and put itself down eight inches away, in a tight pack, at speed, during a leadout.

But chances are you won't experience those conditions on your every day fixed gear. I certainly don't. That's not how I ride my FG.

I wouldn't stress out about it.

It could be an issue, just depends on your particular setup. I have had some minor pedal strike before (just scraping the pedal, nothing serious) while using 170mm cranks and clips + straps. Nothing since going clipless.

165 vs 170.
 

Hi, i commute on a fixedgear eighthinch scrambler v2 frameset. I bought 170mm eighthinch crankarms and egg beater pedals. Had never had an issue of pedal strike.

If your gear is installed then lean your bike and see how far it has to go before the pedal hits the ground.

I have 165mm on my road frame, which happens to have a slightly higher BB than my friend's 62cm Kilo TT, and I can lean the bike farther than I'd feel comfortable leaning while riding. But even with 170mm I could lean the bike a lot.

Thanks for the advice. Id really like to install them on the bike and do this "lean test" but Im building the bike up from scratch and dont have all the necessary parts yet. Also, if I tear up the packaging and instal the cranks, I likely wont be able to exchange them anymore. If it matters, I will be using MKS GR-9 pedals (http://www.velo-orange.com/mksgr9pedal.html).

Even though I dont think I will ever be riding in a way where pedal strike would be an issue, I am kinda paranoid about and my end up exchaning for the 165s just for peace of mind. Plus, I do kinda have shorter legs for my height.

I went with 165mm crank arms when I ordered a Scrambler today. I have a 30" inseam, so it's technically closer to my ideal length than the 175mm cranks I've always ridden on my MTB. I wish EighthInch would list BB height specs, but I can't find them anywhere.

I am glad that i chose 170mm crankarms on my Scrambler. My inseam is only 29.5" and use 175mm on the MTB and 172.5 on the SS roadbike. Me personally, had to go with longer arms for my height to have more torque leverage than short tricycle crankarms. If you made up your mind to go 165mm, then go with that shorter size. Bottom line is that 170mm crankarms work great on the Scrambler and you will not have pedal strike at all!

What he said. If you look at some RD 2's compared to some Dura Ace you would see the difference. I have DA 175's and never pedal strike whereas I did on the Suginos.
It's a bit of a price difference but I got the DA on CL w/ BB and chain ring for a great price.

I think Q factor is going to be a big one. I have ****ty Truvativ Touros in 170mm and I nail the **** out of my pedals on turns

you're getting too worked up over this.

i get pedal strikes a few times with 170's. my bike is a jamis sputnik and i have a low bb. i just take it easier on turns.

I have only ever had pedal strike on platform pedals. Clipless pretty much eliminates the issue.

I experienced pedal strike a couple times on my old conversion, which had 170mm arms. I was able to save it both times and avoid crashing, but one of those caused damage to the pedal and crankarm. On my current fg I'm running 165.

I have 172.5mm Sram Rival road cranks on my conversion. The conversion has a bottom bracket drop of 6.5cm, which isn't as low as a Surly Steamroller, and I am running 28mm Randos too. I just wanted to make sure I had the same crank length on both my fixed gear and my road bike. I have had eggbeaters, MKS Sylvan Track, and now MKS Custom Nuevo pedals and have never had a pedal hit. The bike would have to lean at least 45 degrees over for a pedal to hit.

I am not saying it couldn't happen, but I just don't ride aggressively enough. I have pedaled through plenty of corners on my road bike, too, and have never hit pavement with those pedals. In fact, the only time I have ever had pedal strike is on my old Surly Long Haul Trucker [touring bike with extremely low bottom bracket] with campus pedals and I was trying to strike the pedals.

I have 175mm cranks on my 53cm kilo TT and I pedal strike every now and then but only when im seriously carving through turns. But even then it's only slight contact. Plus the sparks look cool! lulz

i have the scrambler and ran 170s for a little bit before i got 165s. like someone said earlier, unless you have huge platforms or something you'll be fine

Because I dont have everything installed, i cant really measure the Q factor. I will be using a 103mm BB, the pedals are 68mm wide, and Im not sure about the crank arm thickness.