Caliper

Ok, so I've seaeched, and gone through the first 15 pages of threads here and am surprised I don't find more threads about this...

I've got a converted Raleigh FG bike. I've got 280mm from BB to ground. Is this enough clearance with the standard road crankset and 170mm crankarms?

I've ridden it and love the bike, but I'm paranoid about pedal strike. I've cracked two helmets due to pedal strike in the past without having a FG. Thus I'm going slow through the corners, which really sucks because I love taking corners hard. Should I switch to a narrower spindle and 165 crankarms?

MattoftheRocks

That's about eleven inches, plenty. Sure, shorter arms would help, as would lower-q arms and small clipless pedals. One of my bikes is a 700c fg converted mtb. I've never measured the drop but it is really pretty close to level with the axles (really freaking high). With kinda wide 165s and spd size pedals and really sticky 35mm tires I'm still very able to smash the pedals into the ground if I just stay seated through any left turn over 18mph and any right over 12.

One technique I picked up motorcycling on non-crotchrockets is pointing my toes down in turns to feel for the pavement before any bikeparts touch it. With fg it means making it a point of not just dropping into the corner with intent to pop back up, but rather swinging wide and easing down into the lean and contorting your inside ankle to touch the floor with your toes. A secondary benefit is you carry more speed. I'd recommend learning this first.

Another technique that I found I require when I got used to that speed and going faster is standing while pedalling and rocking the bike with the pedal motion- pushing the bars down towards the pavement as my inside foot comes up and then flopping the bike up away as that foot comes down. I have no clue how much more dumb it looks than just going <20mph through turns (probably pretty dumb), what I do know is that on a hot sunny day I could get my bars within a foot of the ground, maintaining nearly the same speed I had going straight and not wreck.

Maybe just sacrifice some webcred and get a freewheel?

europa

Don't worry about it. If you ever NEED to buy new cranks, you can buy shorter but there's nothing wrong with what you've got. Pedal strike tends to only be an issue if you throw a bike into a corner ie, turn sharply which results in a greater lean angle. This is a common technique for riders of geared bikes - sharp turn in, easy out - because they can keep the outside pedal down. On a fixed gear, you learn to take a more even curve through the corner. In the real world, there'll be more things likely to throw you down the road than pedal strike.

SkylarG

I'm riding with only 272mm height, 167.5 cranks, and big BMX platform pedals and have maybe had one close call on very poorly paved road. 280 is the regulation height for many velodromes. You should be fine.

Caliper

Cool. I'd been searching for a number like that but hadn't found the magic search terms yet.

My pedals are so-so. Using the Nashbar pedals that have a medium sized platform one side, SPD clip the other. Of course, that means my clearance is worst when using the clips which is when I'm going faster.

I tend to take an even line around the corner anyways, maybe I need to add some curb feelers to see just how close I am or not.

europa

What's needed on a velodrome is very different to what is needed on the road. Don't be confused by those who imagine fixed gear means a specialist track bike, the two are different and only share the same drivetrain though there is nothing wrong with using a track bike on the road, it's using a road bike on the track that sometimes (but not always depending on the velodrome) that causes issues.

TejanoTrackie 

Just to clarify, the reason for needing a higher BB when riding a steeply banked velodrome is to avoid pedal strike with the right up-track pedal when riding slowly in the turns, particularly at the top. The banking actually reduces pedal strike when cornering at speed.

SquidPuppet

Am I misreading this?

MattoftheRocks

No. I'm a ******.

europa

Am I misreading this?

Dannihilator

Were you able to ride out of it?

MattoftheRocks

Everyday on left turns. Mind you, that's still only leaning my body ~50* from upright, I'm just throwing the bike around like an idiot. I only got close to a foot on a right turn once and slid a bit and have been a wuss about rights ever since, but I'm confident that there's a bigger ****** out there who's out there doin it deeper and harder than me and shredding the edge off of his/her tires.

Edit- now that I think about it, I've always been a wuss about right hand turns, going back to my bmx days... I need to nut up.

IAmSam

Caliper

Good point. What's typical banking on a velodrome?

I did a little experiment last night using a digital angle finder and found I've got 30 degrees to pedal strike. Adding 5mm shims under the wheels to simulate 165mm arms only gave me 1 degree more, not nearly what I was expecting. Flipping my pedals to platform side up gave me 2 degrees, so it seems Q factor and pedal selection may have a bigger impact unless one goes to really short cranks.

Really liking Matt's "velodrome" looks like he could use some broader banking though, haha!

TejanoTrackie 

It varies widely from less than 10 degrees on some outdoor tracks to over 45 degrees on some indoor tracks. When riding on a steeply banked track, you need to ride at least 15 mph in the turns at the top to keep from losing traction, and sliding down off the track. My local track is one of the steepest outdoor velodromes with 44 degree banking in the turns.

Caliper

Haha, now that's cool. There's apparently one nearby in SE Michigan, I really need to try and get out there!

europa

It's fun riding and racing on a velodrome. My local outdoor one is quite safe with a normal road frame and indeed, they'll let you race a road conversion when just trying things out. Our main velodrome is an international standard, indoor job (home of the national track team) and you can only use a proper track bike on it ... but they have regular 'come and try' nights with bikes available for hire at a modest cost. It's well worth giving track a go, you might even get hooked.