A Cycling & bikes forum. CycleBanter.com

Go Back   Home » CycleBanter.com forum » rec.bicycles » Techniques
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Pressures of WTB Horizon 650Bx47 tires



 
 
Thread Tools Display Modes
  #1  
Old November 11th 18, 07:29 PM posted to rec.bicycles.tech
Andrew Chaplin[_2_]
external usenet poster
 
Posts: 6
Default Pressures of WTB Horizon 650Bx47 tires

Has anyone a pointer to a table of pressures for such a tire? Barring that, a formula for their calculation. The tires have to carry a load of about 100 Kg.
--
Andrew Chaplin
SIT MIHI GLADIUS SICUT SANCTO MARTINO
Ads
  #2  
Old November 12th 18, 12:03 AM posted to rec.bicycles.tech
John B. Slocomb
external usenet poster
 
Posts: 312
Default Pressures of WTB Horizon 650Bx47 tires

On Sun, 11 Nov 2018 10:29:03 -0800 (PST), Andrew Chaplin
wrote:

Has anyone a pointer to a table of pressures for such a tire? Barring that,

a formula for their calculation. The tires have to carry a load of
about 100 Kg.

I've got a smartphone app from Berto Tire (downloaded from Android
Play Store) that says for a normal road bike with 650B x 47 tires, 22
lb bike weight and 220 lbs rider, the tire pressure should be 45
psi(rear) and 32 psi (front).

cheers,

John B.



  #3  
Old November 12th 18, 04:31 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 6,415
Default Pressures of WTB Horizon 650Bx47 tires

On 11/11/2018 6:03 PM, John B. slocomb wrote:
On Sun, 11 Nov 2018 10:29:03 -0800 (PST), Andrew Chaplin
wrote:

Has anyone a pointer to a table of pressures for such a tire? Barring that,

a formula for their calculation. The tires have to carry a load of
about 100 Kg.

I've got a smartphone app from Berto Tire (downloaded from Android
Play Store) that says for a normal road bike with 650B x 47 tires, 22
lb bike weight and 220 lbs rider, the tire pressure should be 45
psi(rear) and 32 psi (front).


The typical rule of thumb is to shoot for the tire to sag 15% of its
diameter when loaded. According to that, you'd want your rim to get 7mm
closer to the ground when you load up the bike. I'd just do some trial
and error with the pressures until I got that result. And I'd keep in
mind tire pressure really doesn't have to be extremely precise.


--
- Frank Krygowski
  #4  
Old November 12th 18, 01:32 PM posted to rec.bicycles.tech
[email protected]
external usenet poster
 
Posts: 289
Default Pressures of WTB Horizon 650Bx47 tires

On Sunday, November 11, 2018 at 7:29:05 PM UTC+1, Andrew Chaplin wrote:
Has anyone a pointer to a table of pressures for such a tire? Barring that, a formula for their calculation. The tires have to carry a load of about 100 Kg.
--
Andrew Chaplin
SIT MIHI GLADIUS SICUT SANCTO MARTINO


47 mm wide? I would say 2,5 - 3 bar to start with.

Lou
  #5  
Old November 13th 18, 01:06 AM posted to rec.bicycles.tech
Andre Jute[_2_]
external usenet poster
 
Posts: 8,821
Default Pressures of WTB Horizon 650Bx47 tires

On Sunday, November 11, 2018 at 6:29:05 PM UTC, Andrew Chaplin wrote:
Has anyone a pointer to a table of pressures for such a tire? Barring that, a formula for their calculation. The tires have to carry a load of about 100 Kg.
--
Andrew Chaplin
SIT MIHI GLADIUS SICUT SANCTO MARTINO


A tyre 47mm wide on a suitable rim would probably work around 2.5-3.0 bar. For comfort, I'd start on the low end and try to measure when a rim drop of about 15% of tyre diameter. I rode 60mm wide tyres with more than 100kg load (my own 95kg and 35kg of load at times) on 2 bar and down to 1.5 bar for years, and currently inflate them to about 2.4 bar and ride them down to 2.1 bar because the roads hereabouts have become worse over that period; the important consideration is not to create a fishbite and shortly a fall through a pothole.

In general, it is near-iimpossible to destroy the sidewalls of modern balloons through reasonable under inflation, so if your roads are good, start at the low-end of the spread I give and decide where you want to inflate empirically by steps and test-rides, first lower, then higher.

Andre Jute
Tyres are extremely frustrating for people with rational minds who believe everything should answer to a neat algorithm
  #6  
Old November 19th 18, 05:33 PM posted to rec.bicycles.tech
Andrew Chaplin[_2_]
external usenet poster
 
Posts: 6
Default Pressures of WTB Horizon 650Bx47 tires

On Sunday, November 11, 2018 at 1:29:05 PM UTC-5, Andrew Chaplin wrote:
Has anyone a pointer to a table of pressures for such a tire? Barring that, a formula for their calculation. The tires have to carry a load of about 100 Kg.


Thanks for the useful replies, gentlemen.
--
Andrew Chaplin
SIT MIHI GLADIUS SICUT SANCTO MARTINO

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
OT - Horizon at CERN John Hearns UK 35 May 8th 07 11:37 AM
Hope on the traffic horizon... scotty72 Australia 3 July 3rd 06 08:18 AM
Tires/pressures the pros use? psycholist Techniques 185 February 1st 05 03:31 AM
Haluzak on the Horizon Recumbent Biking 0 July 10th 04 04:50 AM
Best Chain for Haluzak Horizon? Tom Pawlik Recumbent Biking 4 September 20th 03 11:38 PM


All times are GMT +1. The time now is 11:55 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright 2004-2018 CycleBanter.com.
The comments are property of their posters.