what reliant diff ratio

[terry t]

reliant diff ratio on my Goldwing trike
Question is,
the standard gl 1000 is           130-90-17 tyre with a dia 26.21"   3.4    diff
I am running on                     205-55-15 tyre with a dia 23.88"   2.78   diff
looking at running on              205-70-15 tyre with a dia 26.30"  what diff  3.23/1 or a 3.545/1

which one would be best

[fifer]

Try the following speed  calculator

http://www.kabamus.com/garage/gears.html
.
.

[kapri]

You need to know gearbox ratios as well to compare. Reliant is 1:1 in top , does the 'wing have a ratio close to that in top as I thought most bikes are overdriven in top gear?

Saying that tyre diameter is virtually th same so go for the one that matches the 'wing original a set up as it's to do with overall gearing / rolling radius.
3.5 will give you slightly less per gear but create more torque to make up for additional weight.

The end result will be virtually the same as you have now as ( roughly) .2 on diff ratio = 1" on tyre diameter.ie 3" taller tyre is equivalent to approx 3.3 ratio to keep same as you have now.

[terry t]

You need to know gearbox ratios as well to compare. Reliant is 1:1 in top , does the 'wing have a ratio close to that in top as I thought most bikes are overdriven in top gear?

Saying that tyre diameter is virtually th same so go for the one that matches the 'wing original a set up as it's to do with overall gearing / rolling radius.
3.5 will give you slightly less per gear but create more torque to make up for additional weight.

The end result will be virtually the same as you have now as ( roughly) .2 on diff ratio = 1" on tyre diameter.ie 3" taller tyre is equivalent to approx 3.3 ratio to keep same as you have now.

reliant       1st=3.88    2nd=2.05    3rd=1.32    4th=1.00
gl              1st=2.500  2nd=1.708  3rd=1.333  4th=1.097  5th=0.939

[fifer]

Did a quick input on the speed link above and the results were ;

I am running on                     205-55-15 tyre with a dia 23.88"   2.78   diff

205-55-15 tyre
0.939 gearbox  
2.78 diff

4,000 revs ; 108.85 mph
5,000 revs ; 136.06 mph

looking at running on              205-70-15 tyre with a dia 26.30"  what diff  3.23/1 or a 3.545/1

205-70-15 tyre
0.939 gearbox  
3.23 diff

4,000 revs ; 103.09 mph
5,000 revs ; 128.98 mph
...........................................................
205-70-15 tyre
0.939 gearbox  
3.545 diff

4,000 revs ; 94.02 mph
5,000 revs ; 117.52 mph
.............................................................

Edit ; I forgot to change one of the settings but now amended it and the above info was the results I got  { I really should pay more attention when I cut and paste }

[kapri]

You currently run out of puff though don't you Terry ?

[terry t]

You currently run out of puff though don't you Terry ?

what me or the trike Kev 
The trike runs well 70 80 mph. cruises at 60mph at 2800 revs

[stumpy]

136mph 5000 rev ha ha ha lol cough i spat me tea out think ill get a reliant .... must mean kph yawn what time is it i just drempt i had a fast reliant

[kapri]

Gearing on mine works out at 20mph/1000 rpm so theoretical 100mph at 5k. I've had it up to 80, much nicer about 60 though . I think you are too used to hi-revving bike engines Stumpy

Bear in mind that Terrys is a bike engine 'just' a Reliant axle.