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Old 30th May 2021, 21:31   #5626
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Default Re: The Bicycles thread

Need some suggestion/idea in terms of options of filling air in bicycle tire. I have observed that the bicycle tires seem to loose pressure too fast. Almost every 2 to 3 days we need to fill in air to make sure that the air pressure is at it's optimum. I currently have a 12 volt car tire pump which I use to maintain the tire pressure at 45 psi as mine is a hybrid with 700 35c tire. Can the car tire pump be modified so that it can be use without me having to use my car as it is too much of a hassle. I see some options online but they are too costly and at that range would prefer to buy a portable hand pump which I can carry along during my rides. Any cheaper options available so that I can use the car tire pump ?
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Old 31st May 2021, 01:22   #5627
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Originally Posted by sunbaj View Post
have observed that the bicycle tires seem to loose pressure too fast. Almost every 2 to 3 days we need to fill in air to make sure that the air pressure is at it's optimum. I currently have a 12 volt car tire pump which I use to maintain the tire pressure at 45 psi as mine is a hybrid with 700 35c tire. Can the car tire pump be modified so that it can be use without me having to use my car as it is too much of a hassle.?
If tire pressure loss is too frequent ie within days instead of weeks, maybe a scrap metal or a sharp object got lodged in the tire and it causes slow leak. I would first check for it.

Second, I am surprised you use your car's 12V every time you want to pump your bicycle. Why not get a simple hand / leg operated one? OR a portable pump? It should not cost more than 1000INR for a decent one. Why do you want to complicate it?
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Old 31st May 2021, 05:59   #5628
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If tire pressure loss is too frequent ie within days instead of weeks, maybe a scrap metal or a sharp object got lodged in the tire and it causes slow leak. I would first check for it.

Second, I am surprised you use your car's 12V every time you want to pump your bicycle. Why not get a simple hand / leg operated one? OR a portable pump? It should not cost more than 1000INR for a decent one. Why do you want to complicate it?
Was thinking why not reuse a thing if it can be with minor modifications. But if not then will go in for a had or foot pump as there wouldn't be an alternate.
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Old 31st May 2021, 09:00   #5629
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Was thinking why not reuse a thing if it can be with minor modifications. But if not then will go in for a had or foot pump as there wouldn't be an alternate.
Reusing car compressor pump through wall socket is possible only if you have any inverter / DC supply of 12 volts. In my opinion, not worth going that way.

As for foot pump, it is good to pump till 40 psi beyond which it is pain to use. Floor based hand pumps are way to go if you want to pump to 80-100 psi. Speaking from experience of using both. If you buy a hand pump, buy one with gauge.
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Old 31st May 2021, 14:15   #5630
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Originally Posted by carthick1000 View Post
If tire pressure loss is too frequent ie within days instead of weeks, maybe a scrap metal or a sharp object got lodged in the tire and it causes slow leak. I would first check for it.
I have yet to find a tube or valve that does not need topping up for exactly the right pressure before EACH ride, every single day.

Cheers, Doc
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Old 31st May 2021, 14:51   #5631
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Originally Posted by sunbaj View Post
Can the car tire pump be modified so that it can be use without me having to use my car as it is too much of a hassle. I see some options online but they are too costly and at that range would prefer to buy a portable hand pump which I can carry along during my rides. Any cheaper options available so that I can use the car tire pump ?
You can use an AC to DC Converter to run the tire inflator without using the car. But getting a dedicated bicycle tire pump would be better IMO.
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Old 31st May 2021, 15:47   #5632
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Originally Posted by ebonho View Post
I have yet to find a tube or valve that does not need topping up for exactly the right pressure before EACH ride, every single day.

Cheers, Doc
Doc I am new to cycling and have a quick question. My bicycle tires are rated at 50 PSI and I weigh at 73 Kg. What would be the ideal pressure that I should maintain. I have searched across the internet but haven't got a good answer. I even asked the bicycle shop from where I bought the cycle and I was asked to maintain between 40 and 45 PSI. But what I have seen is for optimum riding even a difference of 5 PSI causes a great difference in driving. If a tire is rated at 50 PSI can or should I go till 50 PSI or maintain it below 50 PSI. I hardly or rarely go on bumpy roads.
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Old 31st May 2021, 15:52   #5633
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I have yet to find a tube or valve that does not need topping up for exactly the right pressure before EACH ride, every single day.
Probably no one can find such an ideal setup, due to inherent nature of rubber and valve sealings. The right pressure is an overstatement when it comes to tire pressure. Usually tire manufacturers provide a minimum and maximum pressure and it is upto the personal taste of the rider. Usually the comfortable levels fall somewhere around the average of min. and max.

For eg. See the specs (pressure in bar) of

Vredestein delta cruiser range, predominantly used in city bikes

The Bicycles thread-screenshot-20210531-115958.png

and Vredestein's road bike range of Fotezza Sensor superiore

The Bicycles thread-screenshot-20210531-121929.png
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Old 31st May 2021, 16:43   #5634
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Doc I am new to cycling and have a quick question. My bicycle tires are rated at 50 PSI and I weigh at 73 Kg. What would be the ideal pressure that I should maintain.
Keep them at the max rated limit, but not 1 psi over. Both front and rear. Its ok to do that while they are new. Anyways, 50 psi is nothing for a cycle tyre and you are not going to blow out at that pressure.

When talking of tyre pressure, you should always clarify tyre size as well. 120 psi in a 23c tyre is the same as 90 psi in a 28c tyre.

Quote:
Originally Posted by carthick1000 View Post
Probably no one can find such an ideal setup, due to inherent nature of rubber and valve sealings.
My point was that once you find the ideal pressure for front and rear, you need to check it before every ride to make sure it is at that level.

Across a variety of tubes and valves I have noted that the pressure will be about losing 2-3 psi lower (maybe even 5) when you recheck and re-inflate.

Even if you account for the 2 psi drop in the tube of the pump, that still means a slight drop.

On a big volume MTB tyre it may not mean much.

But on a skinny low volume road bike tyre it is a huge difference. Also when you inflate anything to 110-120 psi, guaranteed you will lose some pressure from even the most finely machined valve. Not so much at the much lower pressures hybrids and MTBs run at.

Anyways, it hardly takes a couple of minutes before the ride. Its not a big deal. Yes, you absolutely must have a floor pump with a dial gauge at home if you are a cyclist.

Cheers, Doc

Last edited by ebonho : 31st May 2021 at 16:54.
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Old 1st June 2021, 06:58   #5635
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Picked up a very good pump for Rs3100. The Topeak Joe Blow Race. It has a single hole for both presta and shrader. Very convenient
I have a Zefal with a toggle operation for pressta and Shrader.

From this pic, I really liked the placement of the gauge in your pump - its the first pump Iíve seen with the gauge at the top. Now that Iíve seen this I canít imagine why the gauge should be at the base of the pump at all. This is a much more logical and user friendly position. I guess I am feeling this more now that I have reading glasses for the first time so have begun to appreciate such small conveniences.
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Old 1st June 2021, 07:12   #5636
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Default Re: The Bicycles thread

Kindly suggest a good fender for my Trek. I will be using it for monsoon riding in paved and semi paved roads. The tyre size is 700x 35c.

Did any one tried the self repairing tubes from decathlon ? Will it be useful in case of small punctures(nail punctures ) ?

Last edited by greyhound82 : 1st June 2021 at 07:15.
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Old 2nd June 2021, 21:54   #5637
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Got a Rockbros "806-TEAM-B" (no idea what's up with the name) mini pump for the road.

I usually carry the now-discontinued Btwin MNP 500 which works okay, but the lack of an extension hose meant I had to hold the wheel while pumping it and the presta valve core was getting bent if one wasn't too careful. Also, the pump is presta-only and cannot be used for schrader valves. Carrying it on the jersey pocket was a chore as I don't like to mount the pump on the frame.

I knew very well that it is difficult to achieve high PSI ratings with very small hand pumps (unless its a high pressure pump specifically for road and is longer than 22 cms .) but I couldn't resist the compact form factor of this Rockbros pump. It weighs under 90 grams, is ~16cms tall with the extension hose tucked in and fits my saddle bag with some coercing.

It is rated for 110 PSI but normal humans cannot pump a roadie to 100 on a mini/micro pump. Anyway, I tested it a couple of times in my home and consistently delivers 20 PSI for 100 stokes. On my 700x25C road tire, I was able to hit 60 PSI. First 100 strokes were easy. The next 100 was moderate effort and the last 100 was hard. If you take a break for a few minutes and are determined, you can definitely do another 100 (it might take 5 more minutes). I was pretty surprised how hard the tyre felt at 60 PSI. I found that unscrewing the extension hose from a presta valve is tricky and you tend to lose some air- but once I fitted a presta-to-schrader adapter to the valve stem and used the correct end of the pump hose, I did not lose any air when unscrewing after inflation.

Hoping to have a positive on-road experience with the new pump on the next puncture.
The Bicycles thread-to_scale.jpg

The Bicycles thread-pump.jpg

Last edited by aah78 : 2nd June 2021 at 23:08. Reason: Pictures inserted in-line.
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Old 2nd June 2021, 23:01   #5638
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Default Re: The Bicycles thread

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Originally Posted by ebonho View Post

My point was that once you find the ideal pressure for front and rear, you need to check it before every ride to make sure it is at that level.
+100 to this rule. Even if one rides on a daily basis.

It's a minor check but the downside is a few psi drop can mean nearly 10 - 20% (or even more) additional effort that one doesn't even realize.
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Old 3rd June 2021, 16:30   #5639
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Originally Posted by itisravi View Post
I usually carry the now-discontinued Btwin MNP 500 which works okay, but the lack of an extension hose meant I had to hold the wheel while pumping it and the presta valve core was getting bent if one wasn't too careful. Also, the pump is presta-only and cannot be used for schrader valves. Carrying it on the jersey pocket was a chore as I don't like to mount the pump on the frame.

I knew very well that it is difficult to achieve high PSI ratings with very small hand pumps (unless its a high pressure pump specifically for road and is longer than 22 cms .)
I have the same pump. Its actually a very high quality pump for the price (at which it was being sold at the time it was available - 500 bucks, MRP was 699/-). Fantastic build quality, solid hefty metallic feel, and very very smooth operation.

Any pump that is good enough to be specifically reviewed by both Bike Radar as well as Road.cc would be a world class product.

https://www.bikeradar.com/reviews/ma...i-pump-review/

https://road.cc/content/review/12652...-500-mini-pump

They do say there are other more effective mini pumps in the same price, but we need to understand that what they say is true for Europe and the US. I've not found a better mini pump for 500 bucks in India for sure.

Its 23 cm long, fits perfectly in your jersey middle pocket, and has an in-built mechanism that boosts the pressure on the out-stroke, making it quite effective.

Its rated for 8 bar or 116 psi, which makes it road bike compatible. Both reviews say that 200 strokes fills the tyre to about 60 psi, and it takes around 400 strokes to actually get anywhere close to a decent get-me-home 95-100 psi.

Unfortunately, I've had to use it only once on the road, and the patch repair never held, and the tyre went flat within the next 100 meters, so I never got to get home and check on my dial gauge floor pump how much I actually managed to fill it (the last 100 strokes are a serious arm workout for sure, but the tyre was nearly as rock hard as what my floor pump achieved 110 psi feels like).

Cheers, Doc

P.S. The trick to keeping the pump stable and not bending/breaking the Presta core, it to use the your index and middle finger over the head of the pump and the thumb clamping around and over the tyre, in a pincer. There are some you tube videos that show how.

Last edited by ebonho : 3rd June 2021 at 16:35.
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Old 3rd June 2021, 17:21   #5640
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Slightly unrelated query - it may have been asked before but I haven’t checked back pages - are the cops in Bangalore stopping cyclists who do long trips solo during lockdown? I am thinking this is a good opportunity to enjoy fitness activities on long empty roads but unsure if I am going to be penalised if I venture out on the roads…
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