Rear Axle/Diff Mounting

[Gilmo]

Hi Guys

As per my intro I recently bought a 1981 Suzuki GS1000G with the idea to build a motorcycle trike out of it. Basically only going to use the front-end and motor from the bike with a diff from a Nissan 1400 pickup (its a small little pick-up we get here in SA and the diff ratio is 4.11).

One thing that is unclear to me at this stage is why is no one welding the diff to the frame? Why is everyone using a clamp setup to hold the diff? I see most use the Reliant diff which we don't get in SA and I thought that mite be the reason. As the diff that I'm planning to use got a cover at the back to remove all the internals I don't see why I would need to remove the whole diff again after build is complete. I could just swop internals if something fails.

Any input would be great.

Thanks

[jinjachin]

reliant diffs are old so the tubes rust plus they are quit thin so most clamp them but some do weld my last trike was welded do some research on ratios the one you have sounds a bit high but im not clued up on ratios so could be wrong . if you start a build tread you will get good info along the way

[Kawazuki]

Nothing wrong with a welded axle providing its square, straight with correct nose / prop angle AND doesn't move whilst welding! Clamping just offers lots of adjustability. Bike engines combined with an extended rev range and generally bigger dia tyres need taller final drive ratios usually sub 3:1 so your 4.1 diff may be somewhat undergeared. I've got an opposite problem - low diff ratio AND small dia wheels and about 55mph top speed LOL!

[Gilmo]

Thanx for the response guys.

I was planning to run 195/50R15 rear tyres giving me a 22.7 inch diameter rear wheel and thought the 4.11 ratio would have worked. As the standard Gs1000g ratio was 3.09 and a diameter rearwheel of 25.5. But I talk under correction as the Gs1000g is old and struggled to get a accurate diff ratio and exact correct rear tyre size.

Your input is appreciated as I'm also learning with the trike thing.

[lepchaun]

try to get something around closer to the 3.11 ratio the reliant is the most suitable over here as it comes in several ratios 2.78 and 3.23 if memory serves me right my Goldwing 1500 is on a 2.78 ratio and runs on 205/55/15 tyres 70mph at 3100 revs

[Gilmo]

Ok it seems the conversion site I used was off.

The new info I have on hand is as follows if anyone can please give input.

The reason for me wanting to try and use the 4.11 diff is due to availability and parts availability in our country. No Railant diffs available and most of our newer rear wheel drive vehicles is bigger pick-up's and think the diff's will be to heavy for a motorcycle trike.

Stock bike with stock rear wheel 120/90/17 and stock 3.09 diff did 120kmh(75mph) at about 3000rpm in 5th gear. (This is according to what i could get online)

Option 1 was to use a 4.11 diff with a 195/50/15 tyre, but after recalculation it seems this mite not work with the high highway rpm.
- Would be doing 120km/h(75mph) at about 4500rpm in 5th gear.

Option 2 is still using the 4.11 diff with a 225/45/17 tyre.
- Would be doing 120km/h(75mph) at about 4000rpm in 5th gear.

Sorry I'm stuck on the other side of the world and small/lighter rear wheel drive diffs seems to be more difficult to source. The 4.11 diff is just the best option if looking at reliability and availability.

Option 2 seems to be the better option as its closer to stock, but still higher rpm. Got no idea of how the low end power is going to be with the added weight and rotating mass. You guys will have to guide me on this as I've never experimented with this type of conversions.

Do I also understand correct that with both these options the bike "should" pull stronger out the blocks that stock rpm range is higher or do i have it the wrong way around.

Sorry for all the questions, but thanx for all the help.

[Kawazuki]

I'm not doubting anyone's research but find it hard to believe a Goldwing is geared that tall - 3000 @ 75mph = 6000 @ 150mph and 9000 @ 225mph ! ! ! Obvs not allowing for drag and guessed redline! My Daily Deauville runs a shade under 5000 @ 70mph which feels about normal and goes to about 110mph at 8500 redline! The internet is not always correct !

[lepchaun]

I'm not doubting anyone's research but find it hard to believe a Goldwing is geared that tall - 3000 @ 75mph = 6000 @ 150mph and 9000 @ 225mph ! ! ! Obvs not allowing for drag and guessed redline! My Daily Deauville runs a shade under 5000 @ 70mph which feels about normal and goes to about 110mph at 8500 redline! The internet is not always correct !

my gw 1500 will rev @ 3100 @ 70mph don't know about the rest of it never checked fastest iv had it was 95mph that was fast enough for me as I was getting a funny smell from the seat

[AngeloftheAbyss]

I'm not doubting anyone's research but find it hard to believe a Goldwing is geared that tall - 3000 @ 75mph = 6000 @ 150mph and 9000 @ 225mph ! ! ! Obvs not allowing for drag and guessed redline! My Daily Deauville runs a shade under 5000 @ 70mph which feels about normal and goes to about 110mph at 8500 redline! The internet is not always correct !

my gw 1500 will rev @ 3100 @ 70mph don't know about the rest of it never checked fastest iv had it was 95mph that was fast enough for me as I was getting a funny smell from the seat

If the funny smell continues hours later it might be time to see a vet

[Kawazuki]

my gw 1500 will rev @ 3100 @ 70mph don't know about the rest of it never checked fastest iv had it was 95mph that was fast enough for me

Love to know where peak torque is with a Goldie as I would suspect most of the time you are operating quite a bit below where the engine is most efficient, usually 4 - 4.5k rpm.