Bomccorkle

I came across this site and saw this

https://www.instructables.com/id/DIY-Bike-Rollers/

anyways seems like a good idea and also an interesting project. does anyone know any specifics on skate bearings??? id od etc. also i know that there are planty of engineers on here so would just a bolt thru the bearing and the frame be solid enough or would their be to much weight there and require a thru rod??

Anyways any help or ideas would be swell.

aljohn

I fancy building a set of rollers myself, I'm in the process of looking at getting (cheap) bearings or rollers. I built a set many years ago. I made a frame out of electrical conduit for free (well, I was at work....) and used three ex conveyor rollers. It worked a treat, but the 3" rollers would have been better if a larger diameter - 6" ? Also the rollers and bearings were steel and when I tried it all out in our kitchen it sounded like a Boeing 747 was trying to land.... after the initial shock my wife banned it, can't say I blamed her. So, I'm after nylon bearings now. If anyone has better suggestions, or knows of cheap bearings in the UK, then please let me know.

corynardin

ID = 8 mm
OD = 22 mm
W = 7 mm
[ https://en.wikipedia.org/wiki/Skateboard#Bearings ]

I am actually not sure you would gain a whole lot (of strength) by having a rod go through the whole thing. I think the key would be to have the bearing as close to the frame as possible.

Bomccorkle

do you think that it would be required that the bearings be double stacked such as a skateboard is or that it would be overkill??? im leaning towards overkill since i wouldnt think that rollers would see nearly the shock that a skateboard would. but maybe i am missing something??? i also assume that a 100mm bolt would fit thru a 10mm bearing??? maybe a skateboard uses a special diameter fastner tho??? anyways going thru the machinists handbook to see what else i can find.

thanks for the input anymore ideas would be more than welcomed. I believe ill get started tomorrow. Ill try to remember to take some step by step pics and post them but i tend to get carried away when Im in the"zone".

Also if anyone has a set of rollers that may be able to give me some of the dimensions off of that would be quite awesome.

thanks again.

Bill in Houston

hmm, i think i would go to vxb.com and look for a bearing with a larger ID than a skate bearing has. 10 or 12 mm, maybe. that way, the bolt supporting it would be that much thicker and stronger.

Bomccorkle

Skate bearings come in 10mm. But nonetheless a good idea:-)

fietsbob

Tell us about the shop you have to machine the rollers and the frame..

Bomccorkle

I am actually a cnc programmer/machinist .I work with 4&5 axis horizontal mills all day. The frame will be of sugar maple though so it looks pretty in my living room. I have a full wood shop at home, its my winter hobby :-)

Bomccorkle

But if you wanted aluminum rollers you should be able to buy d.o.m and weld caps on with bearing bores in them...

unterhausen

rollers always used to be made from wood. I think that a set of maple rollers would look pretty nice.

fietsbob

Ive seen older pictures of roller races, the drums were Big, ,wood, massive,
and seemed to be built in the floor. to make getting on and off easy,

connected to a mechanical display, on the wall to indicate speed, I suppose, a big dial.

OTOH, smaller the diameter, in the ads, are said to increase the effort required,
I don't know. that requires trying several to compare ..

the design with some roller buffers on top of the frame, more recent,
skate board wheels them selves,
to keep the wheels on the rollers, makes sense.

speedevil 

If we're talking about turning some maple/oak/pine rollers, would there be any ease-of-use benefit to make the rollers convex? Doing that with aluminum tubing would be cost-prohibitive but if you've got a chunk of wood in the lathe, making it convex is pretty easy.

I'm just thinking of the old belt-driven farm tools and the belt stayed on the drive pulley because the surface in contact with the belt is convex.

Perhaps it would be easier for new-to-rollers to use? And would the mass of the wooden rollers add some stability?

Just curious.

Bomccorkle

Yes I had thought of convex rollers and I have also thought of using pvc as well and finding a way to pretty it up. The turning blanks I have for the drums are white oak.

Sorry to harp but does anyone have a set of rollers that they can measure the distance(center to center) of the rear rollers and the rear roller to the various adjustment holes for the front roller?? I would like to make the thing adjustable so that just about any bike could use it. I suppose if anyone had a quick answer as to the range of wheelbases on bikes that'd be swell too

corynardin

Sorry, I don't have a set of rollers nor do I have a range for wheel base on different bikes, but you could possibly glue on either a veneer onto the PVC if you went down that road. I personally love the idea of a solid block of maple or oak.

I have seen rollers advertised as having curved rollers to help center, but I have no idea how much they are curved.

Just curiously, have you done any calculations on roller diameter, speed and load on the bearings you are thinking of? I did a quick calculation and it would seem that with a 2" diameter roller going biking at 20 mph the roller (and thus bearing) would be spinning at 3300 rpm. You might want to make sure that the bearings you select and the diameter of the roller will work well with the expected speed that you will be riding.

Can anyone confirm my calculation? Also, it seems like a larger roller would be quieter as it would spin slower.

Bomccorkle

Larger roller=less resistance. Yes thought about the bearings. 3" pvc is actually 3-1/2" od. The bearings I've bought are rated to 180000 rpm at a 500 lb load each and the axles rated at 374 lbs each. Being as the axles and bearings are x six I think I should have enough windage there for even my 240lbs to be good on there.

SumoMuffin

Great ideas here. I'd love to see some pics once you guys get started.

roomservicetaco

From my set of Sportcrafter rollers:

11" c-c between rear rollers
32.5" c-c between front roller and middle roller, with holes at +1" increments thereafter (33.5, 34.5, etc.). You are supposed to set up the front roller such that the bike's front axle is exactly on top of or slightly behind the axle of the front roller. One thought is that you could custom size the frame to the wheelbase of your bike.

Smaller rollers = more resistance. Standard sizes seem to be either 4.5" or 3.25/3.0" (see www.kreitler.com or https://www.sportcrafters.com/ for example). IMO, neither size gives enough resistance for a workout unless you spin at very high cadences (125+). I have not tried the 2.25" that Kreitler sells but their wattage chart looks like it would provide good resistance at typical road speeds (https://www.mountainracingproducts.co...tage_chart.pdf).

Guess what I'm saying is that if you turn your rollers to the larger sizes, be prepared to add a fan, mag, or fluid resistance unit to it. Or, turn the rollers to 2.25" or less.

Booger1

Your a machinist and you can't make a set of rollers.......**********?

Bomccorkle

Excellent thanks. Not a matter of being able to make then its a time vs. Cost thing. The pvc set me back $8 and about 5 minutes on my mites at home..... now turning and truing aluminum...... also I work about 65 hours a week....