Tuesday, 24 July 2018

Thorpy's Guide to Puncture Prevention

Thorpy's Guide to Puncture Prevention


It is quite annoying to have one's plans muddled by a puncture. Either you plan to ride, but can't because of puncture, or a ride is cut short by a puncture. Either way there is no sure fire way to prevent a puncture that will not impede slightly (or massively) on your riding pleasure. I should state that:

  • I am a fan of Shwalbe tires and most of the below relates to that brand. 
  • I have not covered tubeless systems. I know nothing about them.
  • My cycling is not sport based it is commuting, utility based cycling with a rural escapade thrown in on a regular basis.  
In conclusion if you are not fussy and just want to reduce puncture risk to minimum then use a sealant. If you are fussy and want the best options then use a V-Guard tire with a quality tube.  

Both will require some attention now and again, but it will be very infrequent, and will not spoil the enjoyment of your ride. 


Puncture Prevention - Tire Liners - NEVER


Awful (In my experience). 

The idea is that they provide a tough layer between the tire and the tube. They are normally made from a tough plastic. The problem is that they are fiddly to mount, often cause punctures and often do not stay in place whilst inside the tire.

Perhaps the worst of the above problems is the ability of the sharp edges of these plastic strip to cut in to the inner tube. So badly in fact that you will have to throw the tube away! I have only tried one brand (Zefal) and these should be avoided.


Puncture Prevention  - Extra Thick Tubes - SOMETIMES

For down hill racers, or very heavy riders riding low pressure tires over bumpy ground. 

Most inner tubes are made so as to keep air inside of them at pressure. Some tubes such as "thorn resistant" tubes or "down hill" tubes are made thicker than normal so as to give better puncture protection.

This may work against pinch flats (smashing in to a hard object causing a pinch between the rim and hard object) but I have found them to be little good against my main enemy, thorns. I still get plenty of punctures from thorns even with thick tubes.

Puncture Prevention - Puncture Proof Tires - OFTEN


These are often the perfect choice. A balance between puncture protection and performance. 

Now there are many options here, and I will deal with the best. Schwalbe offer some of their tires with V-Guard, this is a thin tough layer in the tire that does not alter the feel of the tire yet provides excellent puncture protection. These tire are very expensive, and there is limited choice, in terms of tread patterns etc.

A more common puncture protection choice is smart guard or kevlar guard, in both these case we see a squashy layer of rubber built in to the tire. A thorn (hawthorn / blackthorn) will go straight through a Kevlar guard tire. However, I have yet to see a thorn go through a smart guard (or green guard) tire which use 3mm - 5mm of rubber to protect the tube.

V Guard or Double Defense (DD) is the Best Option in my Experience


The problem with these green guard and smart guard tires is that they do affect the feel of the ride. Whilst riding green guard tires I notice a deadening of the ride which I do not like. The bike is noticeably harder to pedal .

Apart from "V-Guard" the best option for me in terms of choice and also cost is "Race Guard" this will not stop thorns, but is does stop all sorts of other sharps spiky things such as flints and stones. After 3 years my rear tire (Schwalbe Big Apple) is laced with cuts and "wounds" but examining the inside of tire shows no cuts reaching the inside of the tire.



Puncture Prevention - Sealant - OFTEN

A reasonably reliable choice for many, good for kids bikes, inexpensive and quick to implement. 

Sealants such as tire slime and OKO do work. They do seal holes made by thorns. However, they do not seal well when the thorn remains stuck in the tire, and can also clog the inner tube valve.

If a thorn remains stuck through the tire, the sealant will make a poor seal. The tire may take a few days to deflate, and will hold pressure if pumped up again long enough for most rides. But you will need to remove the thorn to get a good seal again. The easiest way to do this is to examine the outside of the tire until you find the "stub" of the thorn sticking out, then use pliers to pull it out.

I have ridden a bike for over year without having to remove the tube and tire. However I have had to extract thorns on 3 or 4 occasions. This can take almost as long as fixing a puncture if they are hard to find.



Puncture Prevention - Solid Tires & Solid Tubes - RARELY

Unlikely to be acceptable unless you performance requirements are low. 

I tried these many years ago and they were a disaster. They slip on the rim, have a terrible feel, and whilst these they will not get a puncture they will suck 30% of the enjoyment out of a ride. I guess they have there place in a zero maintenance, bike hire situation but if you own you bike, and enjoy riding it they have no real worth.

I slight deviation on these  is a solid inner tube, which is a ring of foam that you squash in to you tire. I have not used these but one would think they suffer similar characteristics to the solid tires, with the added complications of mounting them. Most also restrict the width of tires that you are able to use.

Puncture Prevention - Conclusions

Please find below recommendations:

Small Budget and Moderate Performance Requirements 


A large bottle of tire sealant can be had for £15 that will treat a whole families worth of bicycle tires. I would suggest OKO ATV Tire Sealant , as it comes with a steel valve removal tool (as apposed to flimsy plastic), is much cheaper than bike specific sealants and does the job. 

I use this in all my kids bikes, and my wife's bike, as they don't even notice it is there, and means when we set out for a ride, even if a tire is deflated, I can inflate it again and it will stay inflated for any length of ride. 

Higher Budget and Higher Performance Requirements 

"Race Guard" Tire with quality tube can be set up for around £25 a wheel. A "V-Guard Tire" with a quality tube can be set up for £40 - £50 a wheel. 

The later is a better choice, but you may not find a tire to suite, and the price is a little eye watering. 

Flood Risk Assessment London 

Thursday, 19 July 2018

Schwalbe 13F Inner Tube Review

Schwalbe 13F Inner Tube Review - Intro


A few years ago I purchased some Michelin C6 inner tubes to run with my Schwalbe Big Apples (26 x 2.35). They are a wide tire and I feel  that a wide tube is required. The Michelin C6 is a very thick walled down hill tube, but the valve had sheered off, so I have replaced with a Schwalbe AV 13F, which is a tube designed for use with wide tires.

Wiiiider than the aaavergage tube!
To be clear Schwalbe's Inner Tube Selector Tool , suggests I can use standard width or wide tubes.


Schwalbe 13F Inner Tube Review - First Impressions


The tube is very light for its size. The wall thickness is less than a typical tube, which means this tube can weigh just 185g. A little under double a regular tube. By comparison a down hill tube of the same diameter will weigh 300g +.

The rubber is very supple, and the valve is re-enforced with thicker materials in this area.

I have found these thicker tubes to offer no better protect against thorns than a normal thickness tube. Which leads me to think I will not get any more punctures using a light weight tube.

I I were in to extreme riding, then perhaps a pinch flat would be a problem. But for me that is unlikely.

Re-enforced valve tube interface

Schwalbe 13F Inner Tube Review - Do You Need a Wide Tube?


No this is the main question for me. I suppose the answer in a nutshell is NO, you do not need a wide tube. Many inner tubes offer wide ranges 1.5" to 2.5" for example, which would suite my tires.

But as with so many things bike, we are all of us tinkerers and experimenters in search or our version of perfection.

To my mind a standard high quality tube will be stretched to near its max width when used in a wider tire. Some questions this raises:

1 - Does this mean that the air pressure in the tire is pushing out against the elasticity of the inner tube, rather than the wall of the tire?

2 - Does this mean that the rubber held taught, is more prone to punctures?

3 - Does this mean that tube is less supple? Effecting rolling resistance?

For me these questions and the negligible worries they create are reduced by using a wide tube designed for wider tires. And for the sake of £3 extra per inner tube that is worth it for me.

Schwalbe 13F Inner Tube Review - Conclusions

So I don't really need this inner tube, I am not sure if it offers any advantages, but I feel more comfortable using it. Which in my book is worth something.



Environmental Permit Application London

Friday, 6 July 2018

Reducing Speed of Ebike

Reducing Speed of Ebike

There are many reasons why you might want to reduce speed of an ebike. 15mph is the max legal speed in the UK, so there is one reason. May be you would like to lower speed to match pedal gearing on a single speed bike. . . there is another. 

What I Did:


I attached a 1.2ohm resister to the signal wire of the throttle. There are three wires in a normal ebike throttle cable. They are nromally red, black and green. You need to solder a resistor inline with the green wire.

Addition of this resistor cut the top speed from ~25mph to ~10mph. Measured with GPS on flat road.

I added another 1.2ohm in parrallel to incrase speed, target being 15 mph. However a resistance of 0.6ohm ( 2 x 1.2ohm in parallel) put the speed right back up to 20mph+. 


Guess Work and Assumptions:


So from this we can assume that increasing resistatnce in the signal wire reduces speed. What resistance works on each bike is another question. Perhaps some bikes will require a higher resistivity. 

The perfect resistor for my bike would be between 0.6ohms and 1.2ohms.  But just 0.6ohms differnce can cause a 100% change in top speed, so it is a fine tuning process for sure. I have produced the below graph, which would indciate a resistance of 0.9 ohms would be about right for me.



The graph shows ohms required to give a percentage of original top speed. I know nothing about electronics. I would appreciate pointers in comments if anyone knows something cool.

An Idea!


Could you use an ohm meter between the signal and ground wire to measure resistance with the throttle open and closed. This would give some idea as to the ohm of resister required.




5100 Series and 5300 Series processors in XW6600 and XW8600

5100 Series and 5300 Series processors in XW6600 and XW8600


Here wirtten are findings with regards to use of older processors in newer machines.

What I actually did:


I tried to use a 5335 xeon processor in a XW6600. It does not boot.

What I have assumed from this:


You cannot use an older proccessor from a XW8400 or XW6400 in the newer macines, the processors are not compatable. Which is a shame.

5100 Series and 5300 Series processors will not work in the XW8600 or XW6600. This despite them sharing FSB , socket type, manufactuer . . .even the coolers are interchangeable.

As a side note: Memeory is interchangeable between the newer and older models metioned here, for example Memeory from a XW8400 can be used in a XW6600.

So to conlude I suspect the following processors will NOT work in a XW8600 or XW6600:

  • Quad-Core Intel® Xeon® Processor 5310/ 1.60 GHz,1066 MHz FSB
  • Quad-Core Intel® Xeon® Processor 5320/ 1.86 GHz,1066 MHz FSB
  • Quad-Core Intel® Xeon® Processor 5335/ 2.00 GHz,1333 MHz FSB
  • Quad-Core Intel® Xeon® Processor 5345/ 2.33 GHz,1333 MHz FSB
  • Quad-Core Intel® Xeon® Processor 5355/ 2.66 GHz,1333 MHz FSB
  • Quad -Core Intel® Xeon® Processor 5365/ 3.00 GHz,1333 MHz FSB
  •  Dual-Core Intel® Xeon® 5110/ 1.60 GHz, 4MB L2, 1066 MHz FSB
  • Dual-Core Intel® Xeon® 5120/ 1.86 GHz, 4MB L2, 1066 MHz FSB
  • Dual-ore Intel® Xeon® 5130/ 2.00 GHz, 4MB L2, 1333 MHz FSB
  • Dual-Core Intel® Xeon® 5140/ 2.33 GHz, 4MB L2, 1333 MHz FSB
  • Dual-Core Intel® Xeon® 5150/ 2.66 GHz, 4MB L2, 1333 MHz FSB
  • Dual-Core Intel® Xeon® 5160/ 3.00 GHz, 4MB L2, 1333 MHz FSB
  • Dual-Core Intel® Xeon® Processor 5365/ 3.00 GHz,1333 MHz FSB

Have fun!

Sunlight and Daylight Assessment