They just arrived from unicycle.com today and one of them has a nub type thing that has been grinded off? This nub is on the back of the crank about a centimeter or so up from the axle clamp thing. Are all of these cranks like this? Should i send them an email of complaint. The face of them are also a little dinged up but its just minor and no big deal. But the nub…Its only on one of the cranks and its been grinded off. It just strikes me as not normal and akward. Does anyone know what this is and if i should do anything about it?
Don’t worry about it fluffinator007, it’s just the remains of the chainring nub. My 170s have had it ground off, and I got 145s that have the chainring nub intact. Luckily there is enough room between my frame and the cranks for me not to need to grind it off. In the past Profile made some 145s with no chainring nub especially for unicyclists, but these days as far as I know they only come either with them, or with them ground off by Unicycle.com. I heard rumours about some bike companies making left-side chainrings for bikers who like to grind on the right, so possibly there are some places to get both left and right without chainring holes. I hope you like long cranks, because 170s are huge! Enjoy your profiles, they should last a lifetime.
if anything does happen to it ,uni.com will replace it.
however,i sent mine back because personaly i didnt ask for it and if anyone is going to do any grinding,its going to be me…!..i dont like the looks of a ground down crank and will gladly put in an extra spacer instead of exposing a huge patch of raw medal to the elements.
the grinding job on mine was also quite a sloppy job,done most likely by somone with a hi-speed grinder and a lot of cranx to burn though in one day.(just my guess)…there were hopping and studdering marks.
Some frames need the chainring nub ground down for clearance.
The griding can weaken the crank if the nub is ground down too far and too much of the weld is removed. I had a Profile crank break right at the nub and it appears that it failed because the nub was ground down too far. Hard to know for sure. In any event, the crank got replaced at no cost to me (other than shipping) so it’s all good in the end.
If the nub needs to be ground down for clearance it would be better to only grind it down just far enough to give the needed clearance. Try to avoid griding down too much of the weld.
If you’re concerned about dirt and water getting in the crank through the open nub you can plug the hole with a big set screw. I think it’s an 8 mm set screw. I plugged mine with a set screw and put Loctite on it to keep the set screw from getting loose and possibly falling inside the crank.
Profile does make left-hand drive cranks where the chainring is on the left-hand side of the bike instead of the right-hand side. Unfortunately the left-hand drive cranks from Profile have the chainring nub on both the left and the right crank. So you can’t order the right-hand crank from a left-hand drive setup and get a right-hand crank with no nub. Bummer.
About the set screw idea. What exactly is a set screw and where would i go about finding on of these. Also is there anything i should treat the grinded metal with to keep it from corroding or rusting? Or will this metal not do that?
A set screw can be found at any hardware store. Its pretty much a screw that has no head and is threaded the whole length. They have an allen slot thinger to tighten/loosen them.
Well thank you sir john of hellonwheel. Do you know my good friend Sam?
I have attached a picture of set screws. They have a hex head so you need a hex key to tighten them.
If you’re lucky you can find set screws at your local neighborhood hardware store. But in this age of Home Depot and mega stores you’re not likely to find them. I had to go to a fastener store. Fastener is a fancy name for screws and bolts. These shops generally cater to business and contractors, but some of them sell to the general public. Look in the Yellow Pages under “fasteners”. Bring in your crank and they’ll find a set screw to fit the hole. Hopefully the threads in the nub are still good after it was ground down. If the threads are too messed up you won’t be able to thread the set screw in.
I think the nub is actually an imperial (English) thread and not metric.
I have black cranks so I painted over the area that was ground down with black automotive touch-up paint. I don’t know how critical it is to keep that area from rusting. I did it for cosmetic reasons.
The inside of the cranks is treated with a coating to keep it from rusting inside. When my Profile crank broke in half the inside of the crank had no rust at all. So even if you don’t plug the hole and water gets in the crank it’s still going to be OK and not get rusty inside.
fluffinator: If you are talking about the Sam Cooksey, then yes I know him very well. If you are talking about another Sam, probably not.
Thank you much JOhn_Childs.
And yes thats the Sam.