81 GS 850 G - Shaft Drive Rear tire

[KennyJ]

What is the largest size rear tire I can fit on my 1981 GS 850 shaft drive ? I believe stock was a 4.50 H 17 and I have one with a 120/80 17 I would love to go a little bit larger if possible.

Thanks in advance for any help...

[gs850cafe]

130 90 17 i do belive is the largest...the 120/80 is useable, but probably looks silly and if im right is around 500 or so rpm higher down the highway

and a side not a wider tire dont mean your gonna grip more...i ha ve no chicken strips on my front tire an some on the rear...if you want it to handle upgrade to the gsxr front end and upgrade those 30 something year old rear shocks

[boingk]

Bingo, shocks and fork rebuilds are your best option for handling.

These bikes actually handle fairly well for their age and were praised for it during roadtests in the late 70's and early 80's.

Stay with stock sizes and you won't go wrong. I highly recommend Bridgestone BT-45's as they're a good mix of everything; decent mileage, good grip and reasonably affordable. They come in oddball sizes for our older bikes, too.

Cheers - boingk

[gs850cafe]

i run shinko 230 tourmasters..great grip wet or dry and best wear...my 230s have seen snowy roads and snowy covered gravel and some hard rain stops...needless to say i never went down on account of that

[2BRacing]

I am running Bridgestone Battlax BT 45 in size 130/90-17 on rear and am very happy with grip etc. No issues with clearance to swingarm. Used to run Metzeler before.

[bwringer]

130/90-17 rear, 100/90-19 front.

These bikes will handle unbelievably well with decent shocks, fork springs, any modern tire in the correct sizes, and decent skills.

Boring low-tech 2D devices like Chevys may handle better with wider tires, but you might have noticed motorcycles lean over, so they handle best with the CORRECT size tires.

Get the thing running right, and it's a real giggle -- not much is more entertaining than a GS850 engine between 6,000 and 9,000 rpm.

Squid hunting on an old slow bike is such sick fun...

[gs850cafe]

heres an onboard video of me cornering with the stock sizes on a stock old suspension earlier this year

http://www.youtube.com/watch?v=byV477GUZ_4

[robertbarr]

heres an onboard video of me cornering with the stock sizes on a stock old suspension earlier this year

http://www.youtube.com/watch?v=byV477GUZ_4

Hey, NO SMOKING. Can't you read? Jeez, some people's kids.

And it looks like your tach is a tad out of calibration in the last 20 seconds or so...

[OldVet66]

130/90, 100/90 is a bad combination. 130/90, 110/90 however, is excellent, or as said before 120/90, 100/90. Increasing the back only, causes it to fall into the turns and take longer than it should for the back to catch up with the arc of the turn, not very confidence inspiring. I have run them both ways and know what it does. I am also running Shinko 230's.

[gs850cafe]

Hey, NO SMOKING. Can't you read? Jeez, some people's kids.

And it looks like your tach is a tad out of calibration in the last 20 seconds or so...

hey you got the no smoking joke....my new tire was being delivered that day so i had some fun in our old warehouse

tach wasnt working..had a broken wire that day