Register | FAQ | Members List | Calendar | Today's Posts | Search | Contact |
|
Registered
Members: 666 | Total Threads: 50,910 | Total Posts: 519,174 Currently Active Users: 1,023 (0 active members) Please welcome our newest member, iamwatty68 |
|
|
Thread Tools | Display Modes |
05-03-2021, 12:40 PM | #1 |
Lord of the Rings
Join Date: May 2013
Location: Norwich
Bike: M900sie
Posts: 5,935
|
120/70 on a 620ie?
Could anyone please tell me or guess at what the effect of fitting a 120/70 front tyre on a 620ie would be?
It should have a 120/60. The rear is 160/60. Could the extra height of the 120/70 be compensated for by fitting a different section tyre to the rear or do you reckon it would be okay anyway? I imagine it will just make the steering a little slower? Cheers
__________________
|
05-03-2021, 12:47 PM | #2 |
.
Join Date: Jul 2003
Location: East London
Bike: Multiple Monsters
Posts: 9,731
|
You get a bit more lean before running off the edge of the tread ;-)
Many DD racers used that front with the stock 160/60 rear |
05-03-2021, 12:48 PM | #3 |
Registered User
Join Date: Sep 2020
Location: Stirling
Bike: M1000ie
Posts: 120
|
This seems to be a common thing. My friend's 696 has a 120/70 and I didn't feel like it was a whale when I rode it, although that wasn't anything other than a pootle up the motorway on the way back from buying it and through town to her house.
Will be interesting to see what people say; 120/60 doesn't offer as much choice in terms of brand, I reckon I'd try and find one though when I need to replace the front on my 620ie. |
05-03-2021, 12:51 PM | #4 |
Registered User
Join Date: Jan 2015
Location: Alcester
Bike: M1200s
Posts: 241
|
Hi Gazza, You know I won't know about any clearance issues that are highly likely not to be there, but I can say that I don't think you'll feel any difference at all in normal road use. The difference in any ride height is negligible and shouldn't need any adjusting at the rear.
I say that because the original Yamaha R6 used to have a 120/60 but we all changed to 120/70 for track purposes and that's where speed of turn and feel are just as or more important maybe. We never felt anything other than supreme confidence as it always felt a lot better than any 120/60 item. Though that bike had a 180/55 rear already. The 120/70 raised the front by about 5mm. Well, that's my two penneth right there! :-) As for slower steering, that's not an issue. The 120/60 has a flatter profile that the 70. The 70 will likely feel sharper as it happens. Last edited by Stinger101; 05-03-2021 at 12:52 PM.. Reason: Extra info |
05-03-2021, 12:57 PM | #5 |
Registered User
Join Date: Sep 2010
Location: Leics
Bike: M900
Posts: 2,888
|
Same sized wheel as other bikes so why not the tyre?
I recall back in the 916 and 748 days, the bikes used the same frame, suspension, wheels etc. yet 748s were fitted with a 60 profile front whilst 916 a 70 profile, similarly, at the rear 748 had a 180 width whilst 916 a 190 width. It wasn't long before most adopted the 70 profile front and 180 width rear for both, my understanding was that they tried to sell the 748 as a more nimble bike (presumably to compensate for less power?) and fitting a lower profile front and narrower rear made it tip into a corner quicker but it soon became apparent that it ran out of front tyre/grip sooner due to the lower profile. The narrower rear, however was a good thing.
__________________
M900, 916, LeMans II. |
05-03-2021, 01:22 PM | #6 |
Lord of the Rings
Join Date: May 2013
Location: Norwich
Bike: M900sie
Posts: 5,935
|
Thank you so much my friends that's all good news.
I have a good 120/70 that I'm giving to a mate and I didn't want to give him a tyre that would be likely to cause problems. Would you stick with the 160/60 on the rear? I've never shopped for that size so I don't know what's available. We need something to go well with the Angel ST front, I was going to suggest a Pirelli Diablo? Budget is an issue.
__________________
|
05-03-2021, 01:27 PM | #7 |
Registered User
Join Date: Sep 2020
Location: Stirling
Bike: M1000ie
Posts: 120
|
Might revise my earlier comment then if everyone's saying it's a better option!
|
05-03-2021, 01:32 PM | #8 |
Registered User
Join Date: Sep 2010
Location: Leics
Bike: M900
Posts: 2,888
|
If you really could feel the difference in front ride height that the 70 profile gives over a 60? then you could always compensate by dropping the front of the bike through the yokes but the difference is what, 5 or 6mm? - you probably get that much between different brands and from new to worn.
__________________
M900, 916, LeMans II. |
05-03-2021, 02:26 PM | #9 | |
.
Join Date: May 2007
Location: Stockbridge
Bike: M900
Posts: 1,984
|
Quote:
What rim width do you have on the rear of the bike? The 900 Monster has the 5.5” rear rim which was originally fitted with the scarce 170/60 size tyres. You can fit the 180/55 on those, but for 190 or 200 width tyres you really need a 6” rim. If you’ve got the 4.5” rim you are probably already at the maximum rubber at 160.
__________________
Original and Best since 1993 Last edited by Darkness; 05-03-2021 at 02:31 PM.. |
|
05-03-2021, 03:20 PM | #10 |
Too much time on my hands member
Join Date: Apr 2003
Location: Stonehouse, Glos
Bike: Multiple Monsters
Posts: 2,084
|
120/70 is fine on the front, stick with the 160/60 on the rear.
|
05-03-2021, 03:33 PM | #11 | |
Registered User
Join Date: Jan 2015
Location: Alcester
Bike: M1200s
Posts: 241
|
Quote:
ETRTO manufacturer parameters allow + or - 3.5% and it's very difficult to allow a fixed value into your calculation. In practice the ride height is an average 5 to 6mm. I'm really boring on tyres as they've been my job for 34 years... |
|
05-03-2021, 04:03 PM | #12 | |
Registered User
Join Date: Sep 2010
Location: Leics
Bike: M900
Posts: 2,888
|
Quote:
If so then whilst the top of the tyre would be 12mm higher, the ride height is only 6mm higher as it comes from the axle in the centre (radius).
__________________
M900, 916, LeMans II. |
|
05-03-2021, 04:07 PM | #13 | |
Too much time on my hands member
Join Date: Jun 2007
Location: Forest Of Dean
Bike: S2r
Posts: 3,205
|
Quote:
I like the 916's and the 748's, take the stickers off and you'd not know which was which without a close look.
__________________
"The final measure of any rider's skill is the inverse ratio of his preferred Traveling Speed to the number of bad scars on his body." Song of the sausage creature |
|
05-03-2021, 04:27 PM | #14 | |
.
Join Date: May 2007
Location: Stockbridge
Bike: M900
Posts: 1,984
|
Quote:
https://www.pirelli.com/minisite/pir.../page-392.html
__________________
Original and Best since 1993 |
|
05-03-2021, 04:28 PM | #15 | |
Registered User
Join Date: Sep 2010
Location: Leics
Bike: M900
Posts: 2,888
|
Quote:
Tyres being equal and engine power aside what is the real difference between the bikes with regards to geometry and weight? because the chassis is the same, the engine is the same other than a few internal components and the weight difference is minimal (basically the weight of the missing oil cooler and 1/4L of oil on a standard 748). Now a 748R will have better suspension components and some weight savings over a standard bike along with more power and the more rev-happy nature should make it easier to get on the power whilst the the larger engines have more torque - making it easier for the less race-focused. But given that most people (that I've met) run the 180 rear/70 profile front combination regardless of model then any differences must be largely down to setup and, of course the size of your testicles...
__________________
M900, 916, LeMans II. |
|
|
|