Reducing unsprung weight with lighter tires?

mark_swart
Profile picture for user mark_swart
Posts
2523
Joined
11/2/2011
Location
Chapin, SC, USA
mark_swart
Edited Date/Time 3/20/2012 6:01am
MXA had an interesting article about the suspension performance benefits of reducing unsprung weight, it said there is a significant difference between different tire models/brands. I don't have a rack of tires laying around, has anyone actually weighed them to see which one comes in the lightest?
Right now I'm running Dunlop MX 51 rear, MX 31 front.
|
newmann
Profile picture for user newmann
Posts
24438
Joined
4/1/2008
Location
USA
newmann 3/12/2012 7:29pm
3/12/2012 7:29pm
Icould never find tire weights when I was looking for something light. But sand tires are lighter by several pounds.
mxtech1
Profile picture for user mxtech1
Posts
1968
Joined
7/21/2011
Location
Galesburg, IL, USA
mxtech1 3/13/2012 5:09am
3/13/2012 5:09am
Yeah it's difficult to find weights. I have never seen a magazine shootout where they had a bunch of tires and weight was one of the comparisons.

Typically, sand tires will be the lightest and then soft, medium/intermediate, and hard terrain. The more lugs and less open space the tire has equals more weight. Rubber compound and density also adds to the weight.

The lightest tires I have ever worked worth were Dunlops RR (race replica) 756. These things were a limited production run and man they were light. They hooked up great, but they wore out really fast. I don't think they produce these tires anymore.

You might have some lucking trying to call tire mfg's headquarters and reqeust the information for the tire you are looking for. I'm sure they have the information through their engineering department. Getting them to divulge that information is another story though. Worth a try
beandip
Profile picture for user beandip
Posts
43
Joined
9/27/2011
Location
USA
beandip 3/13/2012 10:08pm
3/13/2012 10:08pm
From another site:

Dunlop 952 80/100/21- 8.5lb
Dunlop 952 110/90/19- 11.5lb
Dunlop 952 120/90/19- 12.2lb
Dunlop 952 120/90/18- 13.2lb
Dunlop D756 110/90/19 = 11.9lbs
Dunlop 756RR 120/80/19- 11.0 lb
Dunlop 756RR 80/100/21- 8.6lb
Dunlop 773 110/90/19- 12.8lb
Dunlop 773 80/100/21- 8.4lb
Dunlop 745 120/80/19- 12.2lb
Dunlop 745 90/100/21- 8.4lb
Dunlop 745 80/100/21- 8.0lb
Dunlop 739FA 80/100/21- 8.1

Bridgestone 604 120/80/19- 12.4lb
Bridgestone 603 90/100/21- 8.8lb
Bridgestone 404 110/90/19- 12.0lb
Bridgestone 404 120/80/19- 12.2lb
Bridgestone 403 80/100/21- 8.4lb
Bridgestone 403 90/100/21- 9.2lb

Maxxis Maxxcross IT 110/100-18 14.2 lbs
Maxxis Maxxcross IT 110/90/19 = 12.9lbs

Michelin MS3 110/90/19 = 13.3lbs

Pirelli Scorpion mid/hard 110/90/19 = 11.7lbs
Pirelli Scorpion mid/hard 80/100/21- 8.0lb

Kenda Millville 120/100-18 13.95lbs
Slayer_1979
Profile picture for user Slayer_1979
Posts
46
Joined
9/25/2010
Location
North Branch, MI, USA
Slayer_1979 3/14/2012 12:06pm
3/14/2012 12:06pm
Mark,

Can you post a link to the MXA article as I'd be interested in seeing what they had to say about the differences? Thanks. I may be wrong but when you say Unsprung weight it makes me think they are talking about Flex in the suspension and bike chassis more than the actual weight of the tire. The flex and tire weight both attribute to the charater and feel of the bike overall which changes how the bike handles, reacts and performs. These type of things intrigue as I have an Engineering background.

The Shop

See All »
mark_swart
Profile picture for user mark_swart
Posts
2523
Joined
11/2/2011
Location
Chapin, SC, USA
mark_swart 3/14/2012 12:17pm
3/14/2012 12:17pm
Sure, here ya go:
http://www.motocrossactionmag.com/Main/News/MX-EDUCATION-THE-HIDDEN-EVILS-OF-UNSPRUNG-WEIGHT-7352.aspx

Unsprung is everything that moves when the suspension moves (tires, wheels, sprocket, brakes). Sprung weight is what's on the frame. However, some of the weight (the actual suspension components) are considered hybrid because they connect the sprung to the unsprung weight. Anyway, they do a much better job of explaining than I do, but it seems to me if you can save 2-3 lbs with a tire choice that should be a noticeable difference, especially when you can't whittle much weight away from the hard components.
Falcon
Profile picture for user Falcon
Posts
12469
Joined
11/16/2011
Location
Menifee, CA, USA
Falcon 3/14/2012 12:36pm
3/14/2012 12:36pm
That article points out something very important: saving weight on your wheels is the best thing you can do, because they are unsprung AND rotating.
mark_swart
Profile picture for user mark_swart
Posts
2523
Joined
11/2/2011
Location
Chapin, SC, USA
mark_swart 3/14/2012 6:43pm
3/14/2012 6:43pm
Makes a pretty good case for thin tubes and aluminum sprockets, that's for sure. But it looks like you might save a pound or two depending on tire manufacturers, which would cost a LOT to save that much weight any other way.
mx5471
Profile picture for user mx5471
Posts
985
Joined
7/10/2008
Location
USA
mx5471 3/14/2012 7:30pm
3/14/2012 7:30pm
I don't think it matters much to any of us, unless we're racing on Speed channel on Saturday night. But it is an interesting question. I disagree with swart that unsprung is is everything that moves when the suspension moves. Everything is moving all the time. Unsprung is every thing the suspension can't control. As in the weight of of everything below where the the suspension connects to the bike. It would be interesting to have a test with average riders to see if it would make a difference. Also, you have different tires for different conditions. It's a question that doesn't have an answer.
Ashman96
Profile picture for user Ashman96
Posts
60
Joined
11/9/2010
Location
New South Wales, AU
Ashman96 3/14/2012 8:34pm
3/14/2012 8:34pm
mx5471 is right Unsprung weight is everything that is not supported by the suspension, hence that name unsprung. Alot of people do not under stand that by fitting heavy duty & ultra heavy duty tubes & billet hub wheels to bikes that add a large amount of weight to a bike. In the worst place. "Unsprung rotating weight" If you have the chance ask your dealer if you can hold a standard inner tube in one hand & a H/D in the other. H/D are nearly double the weight. Same with Talon hubs being machined from billet they are much stronger but also weigh 3lbs a set more than Honda OEM wheels. Which are cast.
mark_swart
Profile picture for user mark_swart
Posts
2523
Joined
11/2/2011
Location
Chapin, SC, USA
mark_swart 3/15/2012 6:18pm
3/15/2012 6:18pm
mx5471 wrote:
I don't think it matters much to any of us, unless we're racing on Speed channel on Saturday night. But it is an interesting question. I...
I don't think it matters much to any of us, unless we're racing on Speed channel on Saturday night. But it is an interesting question. I disagree with swart that unsprung is is everything that moves when the suspension moves. Everything is moving all the time. Unsprung is every thing the suspension can't control. As in the weight of of everything below where the the suspension connects to the bike. It would be interesting to have a test with average riders to see if it would make a difference. Also, you have different tires for different conditions. It's a question that doesn't have an answer.
LOL I don't think we disagree, I just sucked at explaining it!
Based on the posting of tire weights, it looks like sand tires weigh less than hardpack tires in general.
I might not notice the difference, but I am going to stay away from heavy duty tubes and steel/alloy sprockets in the future nonetheless.
newmann
Profile picture for user newmann
Posts
24438
Joined
4/1/2008
Location
USA
newmann 3/15/2012 8:04pm
3/15/2012 8:04pm
I did the whole lightweight project on my 2001 YZ250F. Wanted something between a 125 and 250 2 stroke and the 250F was new on the scene and appeared to be the perfect bike at the time. Only bad thing is that it felt so damn heavy compared to the 125 I was coming off of. I picked up every titanium, magnesium and carbon fiber bit I could get my hands on. I used the Yamaha GYT-R magnesium hubs , stock spokes (lighter than any HD spokes), Excel rims, standard lightweight tubes, Michelin S-12 tires, titanium front brake rotor with ti rotor bolts, Motomaster rear rotor with ti hardware and Afam rear sprocket with ti bolts and nuts. Total weight savings 8 lbs in the wheels alone. Switching between the stock and light wheelsets made a lot of difference in the feel of the bike. It was noticeable. Combined with everything else on the bike, major weight savings. Taking weight off up high makes the bike feel totally different as well. Pro Taper bars, dropped the decomp lever and cable with the '03 camshaft, gytr and Topar mag triple clamps, DSP full ti SX exhaust, DSP carbon airbox, gytr ti subframe, all of the gytr ti bolt sets , axles, pivot, linkage bolts, ti shock spring and dry sumped the engine to get the excess oil weight out of the frame downtube and did away with all the external oil lines, carbon motor mounts took care of most everything up high. Lots of other stuff as well. Classic money pit!
mxtech1
Profile picture for user mxtech1
Posts
1968
Joined
7/21/2011
Location
Galesburg, IL, USA
mxtech1 3/16/2012 6:59am
3/16/2012 6:59am
newmann wrote:
I did the whole lightweight project on my 2001 YZ250F. Wanted something between a 125 and 250 2 stroke and the 250F was new on the...
I did the whole lightweight project on my 2001 YZ250F. Wanted something between a 125 and 250 2 stroke and the 250F was new on the scene and appeared to be the perfect bike at the time. Only bad thing is that it felt so damn heavy compared to the 125 I was coming off of. I picked up every titanium, magnesium and carbon fiber bit I could get my hands on. I used the Yamaha GYT-R magnesium hubs , stock spokes (lighter than any HD spokes), Excel rims, standard lightweight tubes, Michelin S-12 tires, titanium front brake rotor with ti rotor bolts, Motomaster rear rotor with ti hardware and Afam rear sprocket with ti bolts and nuts. Total weight savings 8 lbs in the wheels alone. Switching between the stock and light wheelsets made a lot of difference in the feel of the bike. It was noticeable. Combined with everything else on the bike, major weight savings. Taking weight off up high makes the bike feel totally different as well. Pro Taper bars, dropped the decomp lever and cable with the '03 camshaft, gytr and Topar mag triple clamps, DSP full ti SX exhaust, DSP carbon airbox, gytr ti subframe, all of the gytr ti bolt sets , axles, pivot, linkage bolts, ti shock spring and dry sumped the engine to get the excess oil weight out of the frame downtube and did away with all the external oil lines, carbon motor mounts took care of most everything up high. Lots of other stuff as well. Classic money pit!
How much weight total did you get off that bike? And what do you think your cost was to accomplish that?

They say losing around 9 pounds of weight is the equivalent of gaining 1 hp.

It would be interesting to compare the cost-per-pound lost to the cost-per-hp to build a mod engine. A guy could easily spend $2-3000 on a mod engine build to gain hp, while I imagine it would probably cost about the same to accomplish the weight savings you saw.

It's easy to see how a race bike could cost $5-8,000 just for a weight loss diet and an engine build.
TeamGreen
Profile picture for user TeamGreen
Posts
37286
Joined
11/25/2008
Location
Thru-out, CA, USA
TeamGreen 3/16/2012 11:53am
3/16/2012 11:53am
You guys are on to something...

Don't forget the weight of your tubes, either.

I've been telling folks that you try to save all the "outward Weight" that you can...1st and foremost.

I can make a 230# bike "FEEL" lighter than some 215# bikes (Works).

Seriously...it's all about WHERE you save weight...go look up the test on Jiri Dostal's 2008 KX450F (Dirt RIder...Spring 2008ish)...Jimmy kept asking me,"Why the HECK does it FEEL so light?".

Also, let's not forget how important chassis "set-up" is in this discussion, too.
50dippin
Profile picture for user 50dippin
Posts
361
Joined
10/4/2009
Location
Los Angeles, CA, USA
50dippin 3/18/2012 9:19pm
3/18/2012 9:19pm
Tire companies need to start making Kevlar beaded tires, bmx tire weights were cut in half, however the price pretty much doubled too.
mark_swart
Profile picture for user mark_swart
Posts
2523
Joined
11/2/2011
Location
Chapin, SC, USA
mark_swart 3/19/2012 7:29am
3/19/2012 7:29am
50dippin wrote:
Tire companies need to start making Kevlar beaded tires, bmx tire weights were cut in half, however the price pretty much doubled too.
I was wondering about that myself. But I cringe at the thought of a $250 retail price for a knobby...
scooter5002
Profile picture for user scooter5002
Posts
4748
Joined
6/6/2010
Location
Nanton Alberta, CA
scooter5002 3/19/2012 8:03am
3/19/2012 8:03am
Mark. I was talked into putting a Maxxis sand paddle tire on my 500. While it was awesome traction, (my buddy said the roost was so bad it would blow his feet off his pegs), I knew putting it on, it was too heavy. What I didn't realise was HOW heavy. It absolutely ruined my rear suspension. So much moving mass back there, I couldn't tune the shock to control the compression without making it unrideable. Brutal. It's laying ouside my shop now. 5 hours on it tops. Junk. The science on that unsprung weight is valid. VERY valid.
TX24
Profile picture for user TX24
Posts
2767
Joined
5/7/2010
Location
San Antonio, TX, USA
TX24 3/19/2012 7:50pm
3/19/2012 7:50pm
A friend just ordered me and him mx71 fronts. He got a 80/100/21 I got a 90/100/21 for a little more cushion in the rocks. He said mine weighed a pound more. I hadn't thought about that.
mark_swart
Profile picture for user mark_swart
Posts
2523
Joined
11/2/2011
Location
Chapin, SC, USA
mark_swart 3/20/2012 6:01am
3/20/2012 6:01am
TX24 wrote:
A friend just ordered me and him mx71 fronts. He got a 80/100/21 I got a 90/100/21 for a little more cushion in the rocks. He...
A friend just ordered me and him mx71 fronts. He got a 80/100/21 I got a 90/100/21 for a little more cushion in the rocks. He said mine weighed a pound more. I hadn't thought about that.
Now I'm going to have to go look in the garage at lunch -- I can't remember if I have a 80/100 or a 90/100 for my front!

Post a reply to: Reducing unsprung weight with lighter tires?