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  #1  
Old 12-21-2018, 10:29 AM
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Question Wider rims for better control?

A current trend in bicycling is to increase the rim width while keeping the tire size the same.

Could this be applied to motorcycle wheels???

https://cyclingtips.com/2016/11/the-...e-road-wheels/
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Old 12-21-2018, 06:33 PM
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Re: Wider rims for better control?

It already has Lar. Check out the rim rim widths of the R90S from the 70s. 4" rear rim width and 3.25 front rim as opposed to 5.5" rim for the R1200 and 3.5" for the front
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  #3  
Old 12-22-2018, 08:45 PM
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Re: Wider rims for better control?

Another thing they found with bicycle wheels is better handling/control and road comfort resulted when the tire size was kept the same after going to a wider rim.

For example, a 23 mm wide tire can be used on a rim with an internal width of 15 mm.

However, there was better handling/control and road comfort when the same tire was mounted on a rim with an internal width of 20 mm.

They also talk about decreased rolling resistance with the wider rim, same tire.

An example of the above....

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Old 12-25-2018, 07:30 PM
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Re: Wider rims for better control?

Some of the VW Tuners have gone to narrow tires on wide rims but for different reasons. And they are difficult to mount...

Quote:
Now, you want the wide low look, but to do that you need to by a tire with a wide tread and low ratio and the fender well and steering geometry will allow only so much tire in one place. So, one way to achieve this is stick with a narrow or nominal tread width, say 190 mm, but use a narrower sidewall which will allow the wide look created by the rim, but still maintain acceptable characteristics for the vehicle design.

I will also add that these tires are a “cast iron bitch” to install as most of the tires have a “collapsed” or narrower bead spread and need to be basically “blown” on to the rim. This can be done two ways; the standard way is that most tire machines have a ring that surrounds the bottom of the tire when it is mounted. When you step on the inflate pedal air is injected into the tire through the valve and is also blasted up at the underside of the tire forcing air into the tire and causing the beads to expand and contact the rims and seal enough for air inflation to continue.

Then you have the “Redneck, Hold My Beer and Watch This!” method. I have done this and I am a Redneck, as “red” as they come. When the previous method fails and I am standing there with a beer in hand, that’s been a while mind you since I stopped drinking, probably due to doing things like this; I put my beer down or hand it off to someone equally drunk and reach for the “Quick Start”.

“Quick Start” is ether, yes the “ether” as in what puts you to sleep, but includes stuff you don’t want to inhale. It is normally used to give a shot of fuel to a stalled engine, normally diesels, and it is highly inflammable. I also suggest you don’t throw it in camp fires, don’t ask.

So, you fill the interior of the tire with a long blast of the ether starter and then strike a match. The resulting exothermic reaction or “boom” results in the beads being forced apart and on to the tire rim. If you haven’t set yourself on fire, or burned off all exposed body hair and are quick, you stomp the inflate pedal, the air will then inflate the tire and the previously mentioned ring will blow out any remaining flames.

This procedure is one I must highly encourage you NOT to do no matter the intake volume of beer or the desperation you feel in trying to get the bloody things to mount.

https://www.quora.com/Why-do-people-...s-on-wide-rims
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Old 12-25-2018, 07:39 PM
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Post Re: Wider rims for better control?

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Tyre design is blasting back to the future with car makers set to adopt larger diameter wheels with significantly skinnier tyres than most cars are running today.

Despite decades of tyres getting bigger and wider, there is a new trend towards narrower tyres with a large diameter.

The emerging trend towards skinnier tyres is being driven by a desire to reduce fuel use and carbon dioxide emissions.

"This is the new future," said Damien Hallez, Michelin's head of technical communications. "It helps to improve the energy efficiency [and use less fuel]."

Hallez said every centimetre a tyre increases in diameter there is roughly a 1 per cent reduction in rolling resistance (all things being equal), which is the tyres internal resistance that slows it as it rolls across the ground.

So increasing a tyre's diameter by 2 inches (tyre diameters are measured in inches, not centimetres) would reduce that rolling friction by about 5 per cent.

Car companies are using skinnier tyres to help save fuel.

Having less rubber width also brings improves aerodynamics and further reduces rolling resistance.

"Increasing the diameter we gain in rolling resistance without losing all the security aspects of wet and dry grip," said Hallez.

https://www.drive.com.au/motor-news/...0141004-10qelg
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Old 12-26-2018, 09:02 AM
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Re: Wider rims for better control?

In addition to the trend toward wider bicycle tires, cyclist are using less pressure. Before the switch mountain bike tire pressure was approximately 40 lbs. The wider and tube-less new tire only need about 25 lbs, and get better grip. Perhaps this trend applies more to off-road, GS bike than road bikes.
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Old 12-27-2018, 01:50 PM
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Post Should tires have higher air pressure when load increases???

Should tires have higher air pressure when load increases???

Quote:
The load does not significantly increase the pressure in the tire, but not inflating the tire more will increase friction. This will heat up the tire. Correct pressure ensures correct contact area - preventing wear on the tire, and keeping rolling friction low.

Full answer: Going to use simple math, round numbers (no calculator): 1000 kilo car, 4 tires, 2.2 bar pressure. Contact area for each tire approximately 250/2.2=110 cm2. With the tire 15 cm wide, the contact patch is 6 cm long.

Now "load" the car with 50% more weight (500 kg). The additional contact area needed is 55 cm2 per tire. If you assume that the side walls don't deform, the contact length increases to 9 cm.

The change in volume from this additional flattening of the tire is quite small. Looking at the diagram (and attached snapshot) below, you can compute the volume change (assuming all deformation happens in this plane)

For a constant width W of the tire, the flattened volume is of course Aw.

If we assume to first order that friction is proportional to the volume that is being distorted, you can see that a slightly flat tire (larger contact area) will significantly affect fuel consumption.

How big is the effect? With the numbers I used above, the fractional volume change is only 0.03% (for ri=30 cm,ro=40 cm,w=15 cm). That means that the pressure will not increase due to the deformation of the tire / the additional mass.

And that in turn means that the reason to inflate the tire more is precisely to prevent the increased contact area, which would lead to higher friction and potentially higher temperature.

As @Tom pointed out, under load a tire sidewall will also deform, and this deformation will cause additional wear on the tire. This is another reason why tire pressure needs to be adjusted to the load.

Note that there is a feedback loop - if the tire is underinflated and heavily loaded, it will get hot which will increase the pressure somewhat. But it is better just to start with a bit more air in it...

https://physics.stackexchange.com/qu...ht-of-car-load
Attached Images
File Type: png tire pressure math.PNG (41.2 KB, 2 views)
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Old 01-06-2019, 04:32 PM
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Post Re: Wider rims for better control?

Just changed out the 13mm inside width rims for 17mm ones.

With the 28C tires, it only takes about 50 psi to fully inflate.

Was using 80 for the back and 70 for the front with the 28C on the 13mm.

(BTW, 28C is actually too wide for 13mm rims).

Haven't done a test ride yet.
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Old 01-07-2019, 07:28 PM
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Re: Wider rims for better control?

Also, the back wheel/tire should have 4 mm of clearance on both sides from the chain stays (according to manufacturing guidelines).

And 23Cs on the 17 mm rims also work at 50 psi.

Noted the wider rims increase the amount of air the tire can hold so you will want to increase the size of your inner tubes appropriately.
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Old 01-11-2019, 01:18 PM
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Post Re: Wider rims for better control?

Decided to order a set of 19.5mm rims to use with 23C tires.

Determined that the tire width of the 17mm rims, with 23C tires, is the same as with the wider rims, that is 25mm (see post #3).

The side to side distance between the chain stays at the point where the tire will be at its widest, is 33 mm.

33 - 25 = 8, which gives the recommended clearance of 4mm on each side of the back tire.
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Old 01-13-2019, 08:36 PM
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So the Bontrager wheelset from Trek arrived.

The back wheel is set up for 130mm spacing between the dropouts.

As both of my road bikes are officially antiques (older than 25 years), the spacing is 127 mm (or exactly 5.0 inches).

The Bontragers have ~ 1.8mm spacing washers on each side between the lock nuts and the cone nuts. These serve no purpose other than spacing.

Removal of these results in near perfect alignment (only off by 0.3mm on each side).

The front forks each have 100mm spacing which has not changed over the years/decades. So the front wheel is good to go right out of the box.

BTW, it looks like the 23Cs on the 19.5 rims only require ~ 40 psi.
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Old 01-13-2019, 08:42 PM
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Re: Wider rims for better control?

Quote:
Originally Posted by bobby
In addition to the trend toward wider bicycle tires, cyclist are using less pressure. Before the switch mountain bike tire pressure was approximately 40 lbs. The wider and tube-less new tire only need about 25 lbs, and get better grip. Perhaps this trend applies more to off-road, GS bike than road bikes.

It helps with road bikes too.

For the Professional Road Racers, the better handling, less rolling resistance, and better comfort on the cobblestones due to the lower pressures and different tire profiles are also pluses.
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Old 01-24-2019, 09:24 PM
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Re: Wider rims for better control?

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Old 01-25-2019, 01:25 PM
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Exclamation Re: Wider rims for better control?

WARNING!!!

Some tire makers are concerned about the trend of narrow tires on wide rims.

And have reported a safety concern about instances where the tires have come off of the rims.

It is unclear to me whether this is the result of just the tire being narrower or that combined with the lower pressures used with these setups.

My limited experience is that it is more difficult to mount and remove these narrow tires.

If fact, when used with thicker, puncture resistant inner tubes, you aren't going to be able to remove the tires with tire lifters alone with some brand combinations.

I'm using enough pressure now to eliminate obvious tire compression when on the bike. This works out to ~ 60 psi in back and ~ 50 psi in front.
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Old 01-26-2019, 05:45 PM
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Re: Wider rims for better control?

Removed the spacer on the left side and it is 1.52 mm thick with the electronic digital calipers.

Removal of these from each side will result in ~ 127 mm for a near perfect fit.

I'm going to let the shop remove the right spacer during the first wheel/hub maintenance as the lock and cone nuts on this side are typically very difficult to remove and may require special tools.

Quote:
Originally Posted by BMW
So the Bontrager wheelset from Trek arrived.

The back wheel is set up for 130mm spacing between the dropouts.

As both of my road bikes are officially antiques (older than 25 years), the spacing is 127 mm (or exactly 5.0 inches).

The Bontragers have ~ 1.8mm spacing washers on each side between the lock nuts and the cone nuts. These serve no purpose other than spacing....
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Old 03-08-2019, 09:52 AM
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Post Re: Wider rims for better control?

Have been riding while in Florida.

With 50 psi up front and 60 psi in the back, the bike is very comfortable over expansion joints and rough pavement.

The bike has racing geometry so the steering was a little twitchy to begin with. The additional wheel-with-tire diameter (taller tire profile) may have accented that especially at slower speeds with less gyroscopic stabilization. The larger wheel-with-tire diameter results in decreased trail.

Quote:
Trail is a function of steering axis angle, fork offset, and wheel size. Trail can be increased by increasing the wheel size, decreasing or slackening the head angle, or decreasing the fork offset. Trail decreases as head angle increases (becomes steeper), as fork offset increases, or as wheel diameter decreases.

https://en.wikipedia.org/wiki/Bicycl...geometry#Trail

https://calfeedesign.com/geometry-of-bike-handling/

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Old 03-08-2019, 10:00 AM
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Lightbulb Re: Wider rims for better control?

The Florida streets in our area are sometimes soft sand. This results in a challenge to stay vertical especially with narrow tires.

What seems to help is going to a higher gear which reduces the tendency for the rear tire to spin.

It also appears that loosening grip on the handlebars helps.

Seems like these techniques may also help when on a moto on similar surfaces.
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Old 03-12-2019, 09:42 PM
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Red face Re: Wider rims for better control?

Correction....

Quote:
Originally Posted by BMW
Have been riding while in Florida.

With 50 psi up front and 60 psi in the back, the bike is very comfortable over expansion joints and rough pavement.

The bike has racing geometry so the steering was a little twitchy to begin with. The additional wheel-with-tire diameter (taller tire profile) may have accented that especially at slower speeds with less gyroscopic stabilization. The larger wheel-with-tire diameter results in increased trail.



https://en.wikipedia.org/wiki/Bicycl...geometry#Trail

https://calfeedesign.com/geometry-of-bike-handling/

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