TPMS ... who uses them? what brand?

[melensdad]

aren't those the 89 and 95 in his display or is that something else?

YES, 89 degrees for the front tire, 95 for the rear.

The temps and pressures went up as I rode but I noticed they only went up a couple degrees on the back roads, then when I hit the 4 lane divided highway and the speeds went up, so did the pressures and temperatures. None of that is of any real interest to me.

What I really want to know is if and when the pressures drop.

 

[the Ferret]

Seems like rather useless info to me because you don't know what the carcass temp limits are. I understand the pressure diversion from normal being a heads up.

 

[670cc]

What is the weight of the sensor? Does it affect wheel balance?

 

[melensdad]

What is the weight of the sensor? Does it affect wheel balance?

No clue on the weight. They claim it is under an ounce. They claim it does not affect balance.

I did not notice any balance issues at low or high speeds (up to about 75mph on my ride yesterday)

 

[dduelin]

What is the weight of the sensor? Does it affect wheel balance?

A tad over 5 grams or less than a 1/4 oz balance weight. My static balancer instructions say not to worry over the last 1/4 oz of perfection. They don’t seem to affect balance.

 

[GregC]

this is my TPMS

 

[dduelin]

Today the Goldwing started at 41 front and 42 rear and 74 degrees. 241 miles later in 91 F ambient temperatures:

 

[670cc]

A tad over 5 grams or less than a 1/4 oz balance weight. My static balancer instructions say not to worry over the last 1/4 oz of perfection. They don’t seem to affect balance.

Thanks. Regarding stress on the valve stem, would you consider it safe to add a sensor of this type to a stock straight rubber NC valve stem?

 

[dduelin]

Thanks. Regarding stress on the valve stem, would you consider it safe to add a sensor of this type to a stock straight rubber NC valve stem?

No I would not consider it safe for an extended period. I did this on one of my bikes and after a few weeks the stem had taken on a permanent bend so I knew at speed it was probably bent over. Because that bike had new tires and it would be a while before I would break the tire off the wheel I made a compression tube to hold the stem and sensor in column. I made the tube out of a jumbo Sharpie magic marker cap that was lying on my work bench. One of those "I wonder it this would work" things. I cut the cap to a tube of a length that when the sensor was screwed down to bottomed out on the compression tube. I used it for about 12,000 miles before installing an 83 degree billet aluminum stem..

 

[melensdad]

Santa in the brown truck showed up again today, this time with the replacement TPMS. In the mean time I got the original one to work on my wife's bike EXCEPT for the fact that I cannot get the display to read temperature in Fahrenheit, it seems to only want to display Celsius. Honestly I may just send the replacement back to Amazon in the original, unopened, package. Still deciding. My weather station was displaying 115 degrees this afternoon, which is hotter than the ACTUAL temp. It picks up heat from the wall, so I'd guess it was probably low 90's again. And humid again. And after picking weeds and doing yard work I just lacked motivation to go out and play around with the wife's TPMS display to try to get it to read Farheinheit. Maybe tomorrow.

 

[melensdad]

Just a couple observations, updates.

The unit on my wife's bike is now working, but only reads the temp in Celsius. The replacement unit arrived and when I charged and tested it, the replacement only reads the temp in Celsius. My unit reads in F or C. Both of hers claim to toggle back and forth between F or C but they both seem to be stuck in C. I'm just going to return the new one and be done with it.

The units also read the LAST RIDE's air pressure when you start them up. Near as I can tell there must be a motion switch in the sensors? The CURRENT tire pressure seems to come on after I start riding the bike down the driveway. So you theoretically could pull out and start riding on flat tires if you were not observant.

Switches are multi function switches on these units. I'd prefer a single function POWER switch. I have to hold the tiny "-" button for 6 seconds to turn it on/off. Charge me an extra $1 and give me a dedicated power switch. Small gripe, just being picky.

 

[melensdad]

Been playing around with the tire pressures.

If I recall, the factory tire pressure is 36F/41R

At those pressures I found the bike skittish, especially in some of the rural areas I ride where gravel is often scattered on corners and occasionally out in the road. Especially the rear tire, which, if inflated to 41psi would often climb to 44 or 45psi as the tire heated up. At those pressures the tire was rock hard and if it hit a rock it would typically "spit" it out to one side or the other, causing the bike to be slightly upset, instead of rolling over the rock.

I've now settled on 35F/35R and seem pretty happy with those pressures, the tires seem to stick better to the roadways, the bike is no longer "spitting"gravel and seems much more stable in the corners.

FWIW, when riding on hot/sunny days, the tires will heat up and the pressures will increase 3 to 5 psi. I noticed that when the tire pressure was about 40PSI the pressures could increase up to 5 additional psi. But at pressures in the mid-30's, I only notice the pressures going up about 3 psi. So I'm wondering if higher starting pressures = higher growth in riding pressure do to higher tire temperatures? This is observational, and could be based on weather conditions, as I've not been using the TPMS for very long.

 

[the Ferret]

generally speaking tires can increase up to about 10% in pressure (depending on ambient temp, weight, speed ect) so at 35# you are looking at an additional 3 1/2 pounds or 38 1/2#

and at 42# an additional 4.2 pounds, or 46.2 pounds

this from google

A tire's bending, stretching and deflecting when rolling converts tire motion into heat, also temporarily increasing inflation pressures. It is common for hot tire inflation pressures to increase 4 to 6 psi above “cold” values when driven on hot roads and/or in high ambient temperatures.

 

[dduelin]

When I started using TPMS on a motorcycle I was startled to see cold to hot increases of way more than 10% on rear tires as in 40 cold to 46 hot. 36 or 38 cold would increase more than 16%. On the NC in particular I experimented with higher and higher pressures on the rear Bridgestone to see if I could bring the cold/hot increase to only 10%. I can't remember the exact numbers I used - I think I went to 44 or 45 cold and still saw 10%. The front tire was meh and usually hardly ever increases more than 2 or 3 psi unless really working the front brake in spirited riding with lots of braking but the rear will heat up just regular riding. Fast riding in hot conditions will really hop up the rear tire and the front still not so much. What was neat to see was riding hard in the mountains with intention and seeing the front tire go up when working it hard, then backing off a while and seeing the PSI drop as the tire cooled.

Note that ambient temperatures, rider weight, tire brand and model, speed, and type of riding being done all influence tire carcass heat and thus PSI increases even on the same model motorcycle. In very spirited riding on my heavy ST1300 or Goldwing I would see hot PSI over 50 and that's perfectly normal. On the NC If you start chasing hot pressures down and use low cold PSI to do so then go and ride hard in hot weather the tire carcass gets a lot hotter and that's no good in respect to wear and heat cycles.

Personally after installing TPMS I didn't go below 35/36F and 40/42 rear on Bridgestone T30s or T31s on my 2015. That kept the rear tire from exceeding 10-12% cold hot increases and traction and handling were still great. Bridgestones tend to be very stiff tires and don't flex as much. The 2013 I have now has Michelin PR4s mounted and I only have a couple hundred miles riding with TPMS. I'm using 38 and 40 right now and see 41 and 44 hot but I haven't had it in sustained spirited riding. Michelins tend to have softer more flexible sidewalls and in my experience are prone to scalloping and cupping the tread when using lower pressures. Though it isn't apples to apples the Michelin Road 5s on my RT are wearing very well and stick like glue at 40/42.

Here's an old thread on the subject: https://www.nc700-forum.com/threads/correct-tyre-pressure.11332/

 

[hulkss]

As you described, operating pressure should not increase more than about 15% over the fully rested pressure when you ride. If it does, increase your tire pressure. This is usually only an issue on rear tires as they carry more load.

 

[melensdad]

Well I'm going to play a bit more but I'm very happy with the front at 35/36psi (cold)

I like the feel I get with the rear at 35/36 psi too (cold). I may push that up to 38psi.

At 41# cold, warmed up to 45# it is a bit unnerving going into corners with bits of gravel and having the rear 'spit' the gravel and the bike feel like it loses too much grip in those corners, and those corners are, unfortunately too common in my area.

I weigh, in full gear, about 210 pounds. Add approx 25# for my H&B racks & cases and a few other odds and ends that I carry daily. Never had a passenger on this bike, ever, the Dale's Rack comes in handy just keeping the odd "I'd love you to take me for a ride" passenger off my bike.

Before a trip I may well air it up several pounds to compensate for added weight carried in filled luggage cases.