Wildguzzi.com
General Category => General Discussion => Topic started by: SmithSwede on May 12, 2016, 06:39:45 PM
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My 2013 Stone calls for a 130/80-17 rear tire.
However, I have a goodly supply of 130/70-17 tires meant to be used on a Ninja 250, which doesn't get ridden as much now that I have a Guzzi.
So the cheap bastid gears in my brain start turning.
80% of 130 = 104mm. 70% of 130 is 91 mm. Difference of 13mm, doubled, is 26mm, which is basically an inch.
Does a 1" difference in sidewall height really make a difference. Don't care about speedometer accuracy. Not racing at Isle of Man. Just trying to figure out if it would be a Really Dumb Idea to use 130/70 on the Guzzi, or if that's a non-crazy way to use up tires, providing I ride in a same manner.
Thoughts?
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It will put your bevel box 1/2" lower so it will increase the chance of gear oil migrating from tranny to bevelbox. Also might slow the steering a bit as it will increase rake. The fix for both of these situations is to slide the forks up through the tripleclamps 1/2".
On the plus side, will lower the gearing a bit for better acceleration.
If I had the tire sitting around, I would use it.
If my thinking is wrong, someone will tell us.
Bill
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P... - I would bundle up those tires and sell them on Ebay for a fair discounted price, and then just go and get the right set of tires...
:)
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OK Jay , frugality is one thing , but geez :laugh:
Dusty
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Only thing I would wonder about is if the rim width is OK for the 130/70 tire. It would definitely make your bike lower and gearing lower. I've gone the opposite route putting a 130/90 rear tire on my 750 Breva instead of a 130/80 to make the gearing 250 rpm taller. So in y0ur case you would probably make your gearing 250 rpm lower.
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Unless you measure the difference in the two mounted air up tires you are just guessing as the difference in manufacturing can be bigger than the stated actual!!
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An interesting side note: 1997 Sport 1100i had a 160/70-17 rear. The Daytona RS had a 160/60-17. Chassis was identical.
No , your V7 will not know the height difference in a 130/70 and a 130/80. The slightly shorter tire will cause some speedo error, if your bike's speedo is driven off the transmission. Steering geometry will change, which might slow the steering a little bit, but you could counteract that with dropping the front end.
Otherwise, no big whoop...
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I'd make sure the load and speed rating of those tires will work with the V7, I don't think the size difference is much to worry about.
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Rear tires don't last terribly long. I'd use them. The differences are well described above, and are minor. Either that or ride the 250 more. :)
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Thanks everyone. Seems like no biggie, besides the obvious minor downsides.
I'll probably give this a try when my current tire is "square and bare."
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How old are the tires you want to mount?
Over 5 years I'd dispose of them.
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How old are the tires you want to mount?
Over 5 years I'd dispose of them.
How degraded a tire is after five years really depends on how it's stored. Outdoors in direct sunlight, you're probably right. Indoors, out of UV and temperature extremes, they're probably not much different from new.
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Bought a class C motor home with 7 year old tires on it. They were quality name brand and of the proper rating for the vehicle. They were over 90% UNWORN and looked beautiful. There wasn't a sign of weathering or ageing anywhere to be seem on the tires. Except for the date code they could pass for new.
Told the seller that I'd need tires really soon based on the date code and received a price adjustment.
By the time we reached Texas (about 2,000 miles) four of the six tires had delaminated sufficiently that the vehicle (which never saw over 55 mph on my watch) rode with a constant quiver. Tire shop put the wheels on the balancing machine and hand spun each. The "hops" were easily visible with the naked eye. 4 out of 6 is a pretty significant figure. So arbitrarily I replace tires that have had their 5th birthday. On my bikes I wear them out long before 5 years so it's not an issue. But the V11EV I recently bought came with a 7 year old on the front. Looked okay, handled like crap. Trash guy took it away Wednesday. Bad handling disappeared.
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How degraded a tire is after five years really depends on how it's stored. Outdoors in direct sunlight, you're probably right. Indoors, out of UV and temperature extremes, they're probably not much different from new.
I'm with you on this, but many here don't want to here this. They've been brainwashed by tire companies. :lipsrsealed:
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These are only 18 months old. Stored indoors and even air conditioned.
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These are only 18 months old. Stored indoors and even air conditioned.
That's almost as new as they can get.
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Just this week, I took a 10 yr old Dunlop with 15K miles off of my Eldo. Not because it was terribly worn, but because it had a 1 1/2" sheetmetel screw in it. I had already decided it was time to replace, but the screw ended my procrastination.
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Just make sure you don't end up mixing an radial tyre with a more traditional cross ply which are still available in more traditional sizes you won't like the handling results.