CBF1000

CBF1000 => Tyres and Wheels => Topic started by: Crispy on 23 September, 2019, 03:20:56 PM

Title: Tyre Inflation Frequency
Post by: Crispy on 23 September, 2019, 03:20:56 PM
Hi folks,

Iíve been checking my tyre pressures weekly to maintain optimum performance on my Biffer and noticed that after 3 to 4 weeks the rear tyre was down approximately 10psi and the front 5psi.

I know the CBF weighs 220kg dry and a drop in tyre pressure could be perfectly normal because of the weight of the machine. However, Iíd like to know from other Biffer owners how frequently they need to reinflate their tyres so I can work out if I have a slow puncture or not.

Cheers
Title: Re: Tyre Inflation Frequency
Post by: Shed on 23 September, 2019, 08:50:00 PM
This isn't as straightforward as you may first think, as many factors will effect your pressures. Although I don't think your figures are particularly bad. Just average. Some tyres last months with no change, others weeks.

Tyre age, condition, where you store it, wheel rim bead condition, valve stem condition, ambient temperature, rough roads, potholes, weight on the tyre, the tyre pressure gauge you're using for the reading, the obvious tyre damage/puncture, and of course mother nature, or permeation.

Even with the inflated tyre stood doing nothing, as a rough guide you'll lose 1-3psi per month, this is because the air molecules inside the tyre travel through the tyre via osmosis - but even that rate will vary between manufactures and the ingredients used to make the tyre.

Incidentally, for those that fill tyres with Nitrogen instead of air, you may lose less pressure via osmosis as the Nitrogen molecules are bigger than Oxygen molecules, so may escape from the tyre at a slower rate. Certain quick fit garages try and sell you Nitrogen at a premium  :182:, but for me I'll stick with fresh air thanks.






Title: Re: Tyre Inflation Frequency
Post by: Crispy on 23 September, 2019, 09:28:45 PM
Food for thought there Shed. I use my foot pump to measure the air pressure. My Michelin Road Pilot 2ís should be alright till next year so long as I check the condition and pressures weekly.

Title: Re: Tyre Inflation Frequency
Post by: Silverdart on 23 September, 2019, 09:30:22 PM
I check mine pretty regularly, perhaps every fourth or fifth fill-up, and always before I start out on an extended trip. Sometimes I have to top them up but not by much.

*Originally Posted by Shed [+]
Incidentally, for those that fill tyres with Nitrogen instead of air, you may lose less pressure via osmosis as the Nitrogen molecules are bigger than Oxygen molecules, so may escape from the tyre at a slower rate. Certain quick fit garages try and sell you Nitrogen at a premium  :182:, but for me I'll stick with fresh air thanks.
Like Shed here, I too stick with regular fresh air. Regular air is already about 80% nitrogen so paying extra to get that extra percentage doesn't seem, to me, to make a lot of sense.

Just IMHO.
Title: Re: Tyre Inflation Frequency
Post by: Shed on 23 September, 2019, 09:47:38 PM
*Originally Posted by Silverdart [+]
Regular air is already about 80% nitrogen so paying extra to get that extra percentage doesn't seem, to me, to make a lot of sense.

 :0461: It makes no sense at all. Except for the garages charging you.
Title: Re: Tyre Inflation Frequency
Post by: Shed on 23 September, 2019, 09:53:00 PM
*Originally Posted by Crispy [+]
I use my foot pump to measure the air pressure.

I've not had a foot pump for years, but I do have 7 tyre pressure gauges in my garage, and no two gauges give exactly the same reading on the the same tyre. As long as they are approx the same reading that'll do me!  :028:


*Originally Posted by Crispy [+]
Food for thought there Shed.
 

If you want more food for thought, or are having trouble sleeping, check out The Ideal Gas Law relating to tyre pressure and temperature change.  :800:

Title: Re: Tyre Inflation Frequency
Post by: J-man on 23 September, 2019, 10:04:10 PM
*Originally Posted by Crispy [+]
after 3 to 4 weeks the rear tyre was down approximately 10psi and the front 5psi.
About the same. Nice that you put the question up, I was wondering also  :028:
Title: Re: Tyre Inflation Frequency
Post by: Crispy on 23 September, 2019, 10:16:34 PM
*Originally Posted by Shed [+]
If you want more food for thought, or are having trouble sleeping, check out The Ideal Gas Law relating to tyre pressure and temperature change.  :800:

You know what, Iím going to read that. Readingís a great way to get your head down and learn something at the same time. Win win situation.

Anyway, Iím off for a quick pint.

Until next time.

 :158:
Title: Re: Tyre Inflation Frequency
Post by: wpbrown on 24 September, 2019, 03:54:12 PM
I'd say about once a month or perhaps less. Usually if I feel the handling not the best i check it. Always though if doing a 20+ mile journey.
Title: Re: Tyre Inflation Frequency
Post by: cbrog on 25 September, 2019, 10:35:42 AM
Check mine at least once a week and ALWAYS before any ride , I have a 12v plug in charger £10 from The  Range shop cross reference with digital tyre gauge and it's accurate
Title: Re: Tyre Inflation Frequency
Post by: Gizmo on 25 September, 2019, 04:47:41 PM
Beyond all the variables others have mentioned.

Doing approx 450 miles per week will see my pressures drop by around 0.05-0.1 bar per week.

Apart from a weeklyish check I also get a reminder comes when I roll off the mainstand, if the pressure is down then it just feels 'wrong'.

Personal opinion - never rely on a foot-pump gauge, it's only ever good for going above target pressure and you lose some air disconnecting it as well.
Go over then use a hand held digital to bring down to required pressure.
Title: Re: Tyre Inflation Frequency
Post by: Crispy on 25 September, 2019, 05:15:19 PM
*Originally Posted by Gizmo [+]
Doing approx 450 miles per week will see my pressures drop by around 0.05-0.1 bar per week.

My mileage changes weekly depending on the weather. Your bar pressure converted to psi comes in at 0.7 to 1.5psi a week.

The pressures on my bike seem to be dropping faster than yours, roughly 10psi rear and 5psi front, every 3 to 4 weeks. Think Iíll put it down to tyre quality - Michelin Road Pilot 2 - losing pressure by osmosis. Iím going to look at the code on the tyre wall to see what date the tyre was produced.

Thanks for the tip about using a foot pump and hand held digital gauge, Iíll give it a try next.

Cheers
Title: Re: Tyre Inflation Frequency
Post by: jm2 on 26 September, 2019, 02:08:15 PM
No way can that be normal (unless you were doing mega-miles per week).
Either you have some (small) hole/s in the things, puncture repairs leaking, bad valves (the technical bit/seal or the whole rubber part in the space not sealing) or a terible fit on the rims (corroded rims?).

I saw someone years back showing the cords on a rear - he wasn't even loosing pressure then with no rubber left.

P.S. Or, the wrong sized tyres on the wheels ?
Title: Re: Tyre Inflation Frequency
Post by: Rev Ken on 27 September, 2019, 12:18:53 AM
It is unlikely to be due to your Michelin tyres, unless damaged, as they are some of the best. More likely is any one of the issues already itemised, plus the fact that some alloy wheel rims are porous! I found my CBF1000 tyres lost pressure more rapidly than my BMW F800GT. But not at the rate yours have! There is something definitely wrong. My bet would be a poor tyre to rim seal. If you ever have a wheel off, it would be worth submerging it in water to see if there is any evidence of a leak.
Oh and I agree, NEVER rely on a tyre pump gauge, get yourself a 'proper' tyre gauge.
Title: Re: Tyre Inflation Frequency
Post by: Shed on 27 September, 2019, 07:49:45 AM
*Originally Posted by Rev Ken [+]
Oh and I agree, NEVER rely on a tyre pump gauge, get yourself a 'proper' tyre gauge.

 :0461:
Last year a friend of mine topped up his tyres using garage forecourt tyre inflator (notoriously unreliable), and then spent the rest of the day saying the back end felt a bit 'flighty'. When he got home and stuck a decent gauge on the wheel it turns out instead of the indicated forecourt 42psi it was actually 59psi. Quite a difference.
Title: Re: Tyre Inflation Frequency
Post by: Crispy on 28 September, 2019, 01:18:37 PM
Hmmm... judging by the replies it could simply be the guage on my foot pump giving the wrong reading. I shouldíve mentioned that I changed the valve when I did my wheel bearings as it was cracking around the base. Tyre guy checked the rims and said they were ok.

The code at the end of DOT number is 0817, meaning theyíre only two years old.

My Honda manual says tyre sizes should be 120/70/17 front and 160/60/17 rear, mine match exactly so itís not the wrong tyre size.

General consensus seems to be theyíre deflating too fast. Iíll experiment with a new guage and see what happens. Itís probably a slow puncture, so thinking about saving up for some Avon Storm 3D XM tyres; cheaper than Roadtec 01 and arguably just as good.

 :129:
Title: Re: Tyre Inflation Frequency
Post by: Art on 28 September, 2019, 05:13:58 PM
For my two penneth I kick my tyres every trip, if I get a decent ping its good to go. I'll properly check the tyres once a month for pressure, wear, defects etc. Can't recall how often I've needed to adjust the pressures but I'd guess its around every 3,000 miles or so. Tyre pressures being 35 psi front, 40 psi rear, its not what Honda recommend but thats what I have chalked on the workshop wall, if its +/- 2 psi off that they get adjusted.

If this is morphing into a tyre thread my tyres of choice are Bridgestone BT0-23's. That's what was on there when I got it and they've performed well in the wet, dry & twistys and I'm getting 10,000+ miles from a tyre. Just replaced the rear yesterday after a 1,000 mile sortie around South Wales, it still had 2 mm of tread on it after 10,500 miles.

Happy Days
Title: Re: Tyre Inflation Frequency
Post by: Crispy on 01 October, 2019, 12:48:54 PM
Nice tip Art, just donít think Iím experienced enough for the Ďpingí test  :154:

Had a look at the Bridgestone tyres and they seem like a bargain for that kind of mileage, £185 for a pair.

(https://images.weserv.nl/?url=ssl:www.sportsbikeshop.co.uk/product_images/bridgestone_battlax_bt-023_rear_main.jpg)

I still fancy the Avonís as theyíre made in Blighty and are meant to be designed for British roads. Came across the Avon Trailrider that have off-road capability, could turn the Biffer into a hybrid sports tourer/adventure bike.

(https://images.weserv.nl/?url=ssl:www.sportsbikeshop.co.uk/product_images/avon_trailrider_rear.jpg)

Thanks again.


Title: Re: Tyre Inflation Frequency
Post by: Art on 01 October, 2019, 10:40:52 PM
Favoured the Avon Roadriders on my Triumphs, not such good mileage but hey ho £ for £ they worked for me. Think I'll be sticking to the Bridgestone BT0-23's, they've served me well and most of my riding is done on tarmac, although I've been known to tackle the odd ford now and again.
Title: Re: Tyre Inflation Frequency
Post by: Crispy on 16 January, 2020, 03:15:15 PM
Just posting a quick update on my tyre pressure query and to say thanks for the input from forum members.

As advised I bought a good quality tyre pressure gauge, got myself a guage made by Draper Tools for £11.80 inc P&P.

(https://images.weserv.nl/?url=ssl:images-na.ssl-images-amazon.com/images/I/41dgpiPor3L._SY300_.jpg)

The tyre pressure readings are holding firm with only a slight drop in PSI. The Draper gauge takes the reading and remains on the dial even when you release it from the valve, then itís reset by pressing the button on the side, which is also used to deflate the pressure.

The foot pump was the problem, Iím guessing itís because it had no reset button. Now very happy I donít have to remove the back wheel again and fork out for a new tyre.

Letís Rock  :123:
Title: Re: Tyre Inflation Frequency
Post by: Shed on 16 January, 2020, 09:57:15 PM
Nice one Crispy, a bit of reliability for you now hopefully  :028:


I've got a similar one to that gauge, albeit a digital one:

https://www.sportsbikeshop.co.uk/motorcycle_parts/content_prod/46387

Title: Re: Tyre Inflation Frequency
Post by: Art on 17 January, 2020, 03:21:45 AM
Tyre pressure gauge tool porn ;-)
Title: Re: Tyre Inflation Frequency
Post by: Shed on 17 January, 2020, 10:36:57 AM
 :mfrlol:

Art, try these, they also glow in the dark. Oooh!  :008:

https://www.amazon.co.uk/RHINO-USA-Heavy-Pressure-Gauge/dp/B01J580F2K

https://www.ebay.co.uk/itm/JACO-ElitePro-Tyre-Pressure-Gauge-100-PSI-7-BAR/312703852161?hash=item48ce9a1e81:g:fHYAAOSwQ-BdL-Uu


But, for some proper porn, check out the Longacre beauties here, although I can't quite justify forking out £460 for a gauge!  :005:: https://www.competitionsupplies.com/tyre-pressure-gauges


This one even comes in its own metal briefcase. Double Oooooh!

https://www.competitionsupplies.com/longacre-ultimate-pro-digital-tyre-pressure-gauge-ultimate-pro-digital-tyre-pressure-gauge-2








Title: Re: Tyre Inflation Frequency
Post by: Art on 17 January, 2020, 11:13:03 AM
Very tempting but I'm stuck on the sentimental value of my vintage Dunlop No6 pressure gauge. Appears to be calibrated from 6 -50lbs psi and is probably one step up from a kick of the tyre ping test. But it is what is a 15th birthday present of half a century ago when TT100's were the must have tyre.
Title: Re: Tyre Inflation Frequency
Post by: Shed on 19 January, 2020, 12:08:16 PM
I've got one of those Dunlop gauges somewhere. It's in a tin torpedo tube, like a fancy cigar.

I don't think I'd rely on it for any great degree of accuracy, more like a precautionary reading or rough idea.
(When I couldn't be bothered to get out my £460 Longacre for example  :008:)
Title: Re: Tyre Inflation Frequency
Post by: Art on 19 January, 2020, 12:47:16 PM
In a tin torpedo tube like a fancy cigar, you've been spoilt with the deluxe model ;-) Mine lives in the spare pocket of the little pouch that the tread depth gauge came in, seems to be made for it. Kept handy if I need a  second opinion on the kick of the tyre ping test. Definitely not of a calibrated standard but seems to agree Ī1 psi with the pressure gauges on on the mini compressors supplied in lieu of a spare wheel by Vauxhall and Ford.