Author Topic: Tire pressures for "Classic" spec tires  (Read 977 times)

Online Black Sheep

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Re: Tire pressures for "Classic" spec tires
« Reply #15 on: 21.01. 2021 18:38 »
One other consideration if using 30+ psi is that these pressures are fine for modern bikes with radial tyres and supple suspension. Our bikes don't have supple suspension (who would have guessed) and rely on a bit of tyre deformation to give decent roadholding. With high pressures, there isn't that give which is why they become skittish on corners.   
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Online BSA_54A10

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Re: Tire pressures for "Classic" spec tires
« Reply #16 on: 22.01. 2021 08:28 »
Hi all, I searched the topic in this forum, first. It seems the recommendations about high 20s, front, and low 30s, rear - have been for "modern" spec tires - Avon Speedmasters? I have just been getting Dunlop K70 "replicas". They only cost NZ$175. On the invoice they are called "K70 Classic". I came off my A10 on the 21st November, caught out by a sudden side-gust. Our club repairer is great, he's basically come out of retirement for my insurance job. He said I had been way over-inflating. I said that' what the forums are recommending now for "modern" tires. But he said mine were basically old-spec. It was verified by the wear-pattern. He said it would make it "skittery" which it did seem to be
So, is it that these "classic" tires aren't really modern just because they have been recently manufactured. They still have the "thick walls" like original NOS Dunlops. There are Mitas (Czech) tires on Jay's new A65 acquisition. They were only inflated low by the PO. Looking them up online - they are also called "classic". I have put them (up) to 19 front, 22 rear. I think I will now run my A10 at 21 front, 24 rear. Any comments, thanks..

You inflate the tyre to the makers specification .
Modern tyres run harder than the tyres fitted when the bike was new.
From there you buy a tyre gauge from a push bike shop because they have a smaller range and tend to be more accurate.
From there you start adjusting the pressure in 2 psi increments till they ar comfortable for you.
Adjust them one at time
Remember that if you do it is a single day, the tyres will be getting hotter & the pressure will be increasing .
When you fell you have them right go home & in the morning measure the pressure again.
That is your COLD pressure  .
If you ride like Musky then keep the gauge in your riding kit because servo gauges are rarely accurate.
Bike Beesa
Trevor

Online KiwiGF

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Re: Tire pressures for "Classic" spec tires
« Reply #17 on: 22.01. 2021 11:02 »
Info from dunlop is hard to find on the net, not surprising I suppose given the age of our bikes if they are not “supported” by dunlop.

However, dunlop do “support” modern 500cc single royal enfields, which are pretty similar to our bikes in terms of weight and horse power, and tyre size. They are included on their application documents, and recommend 5he k70 as an approved fitment, with front 24psi, rear 32psi. See pic attached.

To some extent I think this adds weight to the opinion that the newer k70 tyres need to have higher pressures than those made in the 50’s and 60’s.

Just my 2 cents worth.

New Zealand

1956 A10 Golden Flash (1st finished project)
1949 B31 rigid “400cc” (2nd finished project)
1968 B44 Victor Special (3rd project,in progress)
2001 GL1800 Goldwing, well, the wife likes it
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Offline RogerSB

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Re: Tire pressures for "Classic" spec tires
« Reply #18 on: 22.01. 2021 17:14 »
Ha! We've been here before.

I queried K70 pressures with Dunlop in 2018. Here are two of the replies received (note: recommended pressures given in 2nd email).

Mine are K70 Gold Seals and are ok 2 years on and during all of 2020 with a sidecar attached.


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Online Flashgreubon

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Re: Tire pressures for "Classic" spec tires
« Reply #19 on: 22.01. 2021 19:47 »
Hi to all,
I posted a while ago a method to ascertain the correct tyre pressure for your bike, taking in consideration your load and the road temperature.
This applies to all types of tyres and is worth doing if you are in any doubt : it puts to bed any speculations on the subject

https://www.a7a10.net/forum/index.php?topic=13269.msg106923#msg106923

Offline Scott and Jay

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Re: Tire pressures for "Classic" spec tires
« Reply #20 on: 24.01. 2021 01:21 »
Thanks very much for all the replies. I can weigh up all the contrasting input and come up with a plan..

Online Butch (cb)

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Re: Tire pressures for "Classic" spec tires
« Reply #21 on: 25.01. 2021 10:40 »
This dialogue had me wondering how accurate the gauge might be on my old Halfords foot pump. Checking with one of those admittedly somewhat crude blow out rod testers suggests the foot pump is over reading by about 5-7 psi. Maybe I need to get a better gauge so as to be sure. 
Warning - observations made by this member have a 93% unreliability rating.

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Online Greybeard

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Re: Tire pressures for "Classic" spec tires
« Reply #22 on: 25.01. 2021 11:06 »
I'd like to get a good quality inflator for my compressor. Can you recommend one for me?

Online RoyC

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Re: Tire pressures for "Classic" spec tires
« Reply #23 on: 25.01. 2021 11:38 »
I'd like to get a good quality inflator for my compressor. Can you recommend one for me?


I have one like the ones that they use on garage forecourts and the reading is bang on.

It's no good for the BSA though, can't get it on the tire valve.
I use a foot bump and a tire gauge for them.
My bike is a 1958 A7SS
Staffordshire UK

Online Greybeard

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Re: Tire pressures for "Classic" spec tires
« Reply #24 on: 25.01. 2021 16:13 »
I'd like to get a good quality inflator for my compressor. Can you recommend one for me?


I have one like the ones that they use on garage forecourts and the reading is bang on.

It's no good for the BSA though, can't get it on the tire valve.
I use a foot bump and a tire gauge for them.
Why can't the dooberry fit on the wossname? Is it the brake drum that's the problem? What about putting a bend in the metal tube; would that help?

I was looking at a tyre guage like that. They are quite expensive.
https://www.amazon.co.uk/dp/B000RO3P8I/ref=cm_sw_r_cp_apa_i_s8UdGbQRJ8YJZ
If they are no good for the BSA I'm glad you told me. Thanks!

What kind of tyre guage do you use?

Online Butch (cb)

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Re: Tire pressures for "Classic" spec tires
« Reply #25 on: 25.01. 2021 16:29 »

I have one like the ones that they use on garage forecourts and the reading is bang on.

It's no good for the BSA though, can't get it on the tire valve.
I use a foot bump and a tire gauge for them.

https://www.ebay.co.uk/itm/90-Degree-Angle-Tyre-Valve-Extension-Adaptor-Motorcycle-Motorbike-Car-Bike/113766791704?hash=item1a7d077a18:g:ihMAAOSwUn9aAX5d
Warning - observations made by this member have a 93% unreliability rating.

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'58 Iron Head Flash Bitza


Online RoyC

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Re: Tire pressures for "Classic" spec tires
« Reply #26 on: 25.01. 2021 17:09 »

I have one like the ones that they use on garage forecourts and the reading is bang on.

It's no good for the BSA though, can't get it on the tire valve.
I use a foot bump and a tire gauge for them.

https://www.ebay.co.uk/itm/90-Degree-Angle-Tyre-Valve-Extension-Adaptor-Motorcycle-Motorbike-Car-Bike/113766791704?hash=item1a7d077a18:g:ihMAAOSwUn9aAX5d


I have got four of those extensions, they are no good, they all leak giving you a slow puncture, unless you remove them after inflating the tire but you will have to over inflate to compensate for the air loss while removing it.
My bike is a 1958 A7SS
Staffordshire UK

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Offline muskrat

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Re: Tire pressures for "Classic" spec tires
« Reply #29 on: 25.01. 2021 20:17 »
G'day Fellas.
I use one like this https://tinyurl.com/y4elguon
Then I double check pressure with a digital.
Cheers
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