Tyres diameter and gearing

[Donut]

Hello everyone,

Can someone help with the following? Thinking about triking a V Max with a spare reliant axle that I have with a set of big (diameter ) wheels about 32 inch instead of the normal 24- 25 ish and wondered if the motor will be ok with this high gearing or if it is going to be like starting of in 4th gear all the time?
Can't see any info about this or on the net
cheers

Donut

[ByzMax]

There is a section on the motors section (not the forum) that allows you to calculate it.

What you/we need to know is the following.

Original diameter of rear wheel with tyre fitted.

Ratio of final/bevel drive of yor Vmax. 

Ratio of the reliant axle you have.

Diameter of new wheels with tyres fitted.



Axle/Diff/Final Drive Ratio is number of turns of the propshaft per revolution of the rear wheel/s

[BikerGran]

Hm, not sure if the gearing of the Reliant axle will do justic to the power of the V-Max.  It's brought the top speed of my GT550 down from about 100 to about 80 (and that's when I get a chance to wind it up).  I guess that's why you are asking about the wheel sizes and I suppose it would do the job but....... there might be something better out there?

[Donut]

Yes probably is something better but I have a spare axle and other bits which would be a shame to waste.
My thinking was the bigger wheels would let it cruise better ie would raise the top speed a bit but am worried that even a v max would struggle with starting off etc
cheers

[VmaxTriker]

I got vmax trike, I cant say for sure but I think you would have problems with 32inch dia rear wheels.

Hill starts might be difficult and especially when fully loaded 2 up etc, plus the fact the trike will most likely be leaning forward all the time which will get uncomfortable.

Personally I wouldnt do it.   I got 17inch rear wheels with low profile tyres and that gives me 3800rpm at 60mph.. which is exactly same as what it is for the bike in standard form.

But my diff is a BMW or MERC

[ByzMax]

Reliant is fine just make sure you match the diff ratio to original final drive and wheel size. You need to aim for the same or just lower top speed (5% lower).

Remember the trike will be alot heavier than the bike and will have about 16" of rubber in contact with the road rather than 2-3" resulting in strain on the transmission components

[Donut]

Cheers for all the replys.
re leaning forward I am making a frame so can adjust to suit and keep everything level. Have another option of 29inch diameter but same problems apply i supppose
Why is nothing simple in life!!

[BikerGran]

Because it would be boring!