Rear tire for 1980 Gs1100E??

[chuckycheese]

As some of you know, I just purchased a beautiful '80 GS1100E. The guy that previously owned it replaced both tires...but the rear ain't right. Somebody put on a 110/90-17 IRC Durotour...a fairly decent tire (?) but the wrong size. (The book says '4.50-17' but, that was the old days.)

I think, based upon what I've read, that I need a 120/90-17 or a 130/90-17. What do you GS1100E guys think? Also, is there any difference between tire sizes between 1980 and 1983 with the GS1100's?

Also, what do you think of IRC tires? I've used their tubes in the past with no problems.



Thanks, guys...as always!\\/

[lurch12_2000]

tire size

I have an '83 GS1100G and my rear tire is a 130/90-17 after I converted the old measurement and also checked the manual. I think your's should also run a 130/90-17(4.50-17) on the rear.

[rphillips]

The 110 won't create any problems, unless you are a REALLY agressive rider, just a slight bit narrower than a 4.50. After it's worn out, replace it with a 120 or 130. I've not had any problems with IRC, As a matter of fact many GS's were originally equiped with IRC tires. I know all the 1100E's had 17" rear tires. Not sure, but I think they were also the same width.

[Steve]

If you do the math, a 4.50 converts to 114.3 mm, so a 120 would be the most direct replacement, but a 130 would also do the job.


.

[bwringer]

Most examples of the 1100E are wearing 130/90-17 rear tires and 100/90-19 front. This happens to be the same tire sizes found on the G model 850, 1000, and 1100 shafties.

When in doubt, ask "what would Joe do?". It turns out that Joe Nardy's 1100E is using Pirelli Sport Demons in those sizes.

The Pirellis are without a doubt the finest and most amazing-feeling sporty tires money can buy.

The new Avon RoadRiders are also excellent, and last a bit longer than the Pirellis. They are a bit sharper in profile and thus turn in a bit quicker than the Pirellis. You may or may not prefer the quicker steering -- it's a matter of taste.

Metzelers are also excellent, and have many rabid fans. There's also the superb Bridgstone BT45 and Michelin M50.

Continental also makes the Milestone in this size, but it's not a V rated sporty tire.

A bit beneath those front runners are the Asian brands -- Cheng Shin HiMax, Kenda, Duro, and IRC.

Personally, I can't recommend the Dunlop 404 or the Bridgestone S11 Spitfire. In my experience, both grip well at first, but they wear very quickly and develop bad habits as they wear. The Cheng Shin Barracuda and Marquis are also outdated designs and are not recommeded, although the HiMax is a fine tire with excellent pricing.

[chuckycheese]

Thanks!

You guys are absolutely awesome, as usual!!! I'm running GT501's on my GS750L (which I really like) but think I'll go up to a 130 on the 1100. Many thanks to RPhillips, Steve, BWringer and Lurch for your comments.

Sometimes I think I know what's best but...it's always better to have a little help!:-D

By the way, Steve, I figured the mm/inch math gig but had the feeling that tires have changed in a number of respects since then and that people seem to be running bigger tires.

[chef1366]

I also run the GT501s. Good tire but I wear a rear a year. If you need an extra rear rim I have one that's perfect. Let me know.

[scotto58]

Hey Chucky

Just my 2 cents worth...that Durotour won't last. Put one on my 850 2 years ago(couldn't find anything else at the time) it was toast after 1 season of riding. I am not an aggressive rider. The tire handled well but didn't last.

Scott

[Steve]

By the way, Steve, I figured the mm/inch math gig but had the feeling that tires have changed in a number of respects since then and that people seem to be running bigger tires.

Yeah, I figured that most people know how to convert from the old sizes to the newer metric designations, but there just might be someone out there that didn't know that yet. 8-[

And...bigger tires might look great, but are not always better for handling. If you install a larger tire on the same (narrow) rim, the profile will be pinched into a tighter radius and you might actually have a smaller contact patch on the road. :shock:


.

[Nessism]

And...bigger tires might look great, but are not always better for handling. If you install a larger tire on the same (narrow) rim, the profile will be pinched into a tighter radius and you might actually have a smaller contact patch on the road. :shock:

.

A 130 is really pushing the limit on most GS rims. How wide is the rear wheel? The 120 on my 550T is wider than the stock 4.50 x 17 that was on there from stock.

[chuckycheese]

Thanks!

Bill....Thanks for the offer. The wheel is stock so I should be able to work with it.

Scotto....The durotours were on it when I bought the bike; and, they're almost brand new so I feel like I should get some mileage on them rather than dump them both.

Steve....I totally agree!

Ness....130's are specified on my Gs750 but I know the rims on the 1100 are narrower; I'm gonna measure them to see what I've got. Maybe the 120 would be a better idea.

[lurch12_2000]

more data than you need?

OK, here are some thoughts for debate:

Stock front rim for GS1100E and G models is 3.50v19
3.50 inches - converts to 88.9 mm
Stock rear rim for GS1100E and G models is 4.50v17
4.50 inches - converts to 114.3 mm

These sizes are taken directly from the 1980-83 GS1100 E and G model brochures and conversions done from converter tools I found on the Web.

If you are using the 100/90-19 for the front then this is 12.5% greater than the value of 88.9 mm
So if you apply the same 12.5% ratio to the rear wheel of 114.3 mm you come up with 128.59 mm - which is closer to a 130/90-17 tire

I think you have to factor this in for proper wheel width to rim width and realize the 130 is properly sized for the stock rim.

I would also go with the 130/90-17 rear because the GS1100 is a heavy bike with a lot of torque and this size would provide greater contact and material to withstand the load.

I'll agree that narrower tires could provide better and quicker handling on my old British bikes (Triumphs and Nortons) I owned but still think the 130/90-17 is your best solution on the GS1100 model.

Now if I only had better things to spin my brain cycles on....
By the way I recently put Cheng Shin Hi-Maxx tires (100/90-19 front and 130/90-17 rear) on my GS1100G and like the handling, looks, and ride. Since I only have a few hundred miles on them I can't report on wear life span.
Steve

[chuckycheese]

Not quite!

Your numbers are all right except for one thing.....the 4.5 that you refer to is not the width of the rim; it's the width of the tire!!

[lurch12_2000]

have to check??

Chucky,
Good point???- now I'll have to go out to my garage tonight and measure first hand.
Still the ratio of going 4.50in(114.3mm) to 130mm conversion for the rear is the closest to converting 3.50in(88.9mm) to 100mm for the front when using the current size listings for buying bike tires.
Is this enough of an argument for you to run out and buy a new tire to replace your relatively new 110 rear tire? I'm not sure, but if you light up your tires alot then maybe...then you can buy two of the Hi-Maxx for the price of one Dunlop, Pirelli,:-D....

[chuckycheese]

Ratios

Yeah, I see what you're saying about the ratios being the same but...according to the tire charts (take a look at Dunlop's, for example), the conversion ratios are different for front and rear tires.

I think it's kind of a confusing issue and not as simple as it would seem!