Manky Monkey Motors

Hi I know I have asked what diff is best for my trike with a reliant axle A 3.23 or B 2.73
I am running the B type on 205-60-15/ 25"dia tyre  now when cruising at 60 mph at 3000 rpm in top gear

what I want to know is this looks fine say for a car. but the original spec for the Gl1000 is
Final Drive     3.400
Tyre              100-90-19 app 26" dia
Max Power     78hp@7000 rpm
Max torque    61lb/ft @5500 rpm

I also get a lot of clutch chatter this may be the plates are worn or it could be the gearing ???
any views or ideas
   

What gear ratio is it doing the current speeds in as that will make the difference to the calculations just so we can compare apples with apples ;) I always use 1:1 ( normally 4th on MOST car gearboxes) ie I know the final drive is 3.4 but what is your current gearbox ratio at those speeds.

Driveline 'shunt' is normally caused by too tall a gear for the torque available.

Hi Kev the gear ratio for the gl1000 is
1st  2.500--2nd 1.708--3rd 1.333--4th 1.097--5th 0,939--final drive 3.400
it was in 5th gear doing 60mph@3000rpm
compared to the reliant
1st 3.88.1--2nd 2.05.1--3rd 1.32.1--4th 100.1. the final drive 2.73/3.23 or3.55 I under stand reliant used the same gearbox just changed wheel size  ??? may be wrong

Reliants swapped between 13s and 10s I believe when supply of 100E steel wheels stopped? Lots of old For Popular 100E parts used in Reliant when you know what you are looking at , especially steering boxes :)

Using your trike in 4th and seeing mph/1000 would give a better direct comparison. Roughly 10% difference between your Gl gearing and Reliant gearing when the Reliant is in 4th 1:1 compared to your GL in overdrive.9 gearing. I'll have to find an online calculator , I'm not up for 'sums' at the mo :(

The following is what I use ;

https://sites.google.com/site/fifersrelianthintsandtips/speed-calculator-chart
.
.

Loading my info onto this. 205/60.15   5th gear .939   diff 2.79  shows @3000 rpm I should be doing 84.27 mph

I am doing @3000 rpm 60mph I know that my speedo is correct as I have compared it with my garmin zumo550 sat nav 

Kev next time I am out I will check it in 4th @ 1000rpm if it will run in 4th that low rpm

3000 will be fine Terry, asl ong as it's a number easily divided to get back to what the actual 1000rpm speed is.

Terry, I think the reason things don't add up may be due to some errors.
If like most trike owners you are running your tyres soft, you may have to make allowance for this. Also the tacho may not be reading accurately.
If you assume the tyre is acting more like a 205/50 and the diff is actually a 3.54 then the mph comes out at 61 @3000
Do you know for certain the diff ratio ?

Dave. yes I can under stand that. I am running with 25psi in the tyres which makes them app 15mm smaller in dia. the diff is B type 2.79  39 teeth on crown and 14 on pinion. I also have a 3.23 and 3.54 diffs. the rev counter is not far out as when I set up the timing I had a separate rev counter connected with the strobe light
I am only checking this out as the RPM and REVs are as you would get on a car. but this being a bike engine the rev band should be higher  ???
I will check the spare diffs I have in the garage

Hi there,
              Just joined MMM, read this post and thought I would let you know when I was building a locost seven I came across a online downloadable gearing calculator . From what I can remember it was called "gear calc" I'm sure a google search would find it. Very easy to use, you can save each scenario you enter , gives you a graph curve and print out the results for easy comparison .

Might be this one. ?


http://locost7.info/gearcalc.php

Yes, cheers that's the one. I found it very useful for matching engines ,gearboxes , drivetrain and wheels/tyres.
Cheers Phil