Speedometer buying advice

[fairyhedgehog]

I'd like to join in some local cycle rides for beginners but I'm worried the pace may be too fast. This one is one of the slower ones and it's averaging 10 - 12 miles an hour. I've used google maps and walk, jog, run to measure how far I go and then tried to work out my average speed, and I reckon it's about 8 mph which is really dawdling. I enjoy dawdling but I'd also like to be able to ride in company!

I was wondering about getting a speedometer to give me a more accurate idea of how fast I'm going at any given time so I can work on going a bit faster. I'm not sure I want one where you have to fix something to the wheel because my husband has had problems with those but getting one with GPS might be a bit pricey. I thought you folks might have some good ideas!

 

[roadrash]

@fairyhedgehog do you have a smartphone, if so you could use strava , its free to download and use ,and would give you your speed, allthough i personally havent had any problem with this type that uses a magnet on the wheel.

http://www.decathlon.co.uk/count-4-wireless-cycle-computer-id_8173017.html

 

[blazed]

The Edge 200 is the best low budget one around. Also your speed will increase when you're cycling in a group.

 

[fairyhedgehog]

@fairyhedgehog do you have a smartphone, if so you could use strava , its free to download and use ,and would give you your speed, allthough i personally havent had any problem with this type that uses a magnet on the wheel.

http://www.decathlon.co.uk/count-4-wireless-cycle-computer-id_8173017.html

Thank you! That's useful to know, both about the smartphone app and the magnet thing not always giving problems! I could even use both and see how well they match.

 

[fairyhedgehog]

The Edge 200 is the best low budget one around. Also your speed will increase when you're cycling in a group.

Maybe I can persuade Santa that I deserve one of those this year!

I hope my speed would increase with other people, but sometimes I've found my speed was really slow even when I thought I was hurrying!

 

[Berk on a Bike]

Any group ride specifically aimed at newcomers to groups should ensure no one gets left behind really.

 

[Banjo]

I have two bikes with the basic Halfords wireless cycle computer and both have worked well over a lot of miles. They are about £20.

Definitely go for a wireless one .They look much neater on the bike.

Re cycling with the club , most clubs/groups will let you ride a few times before joining to see if its for you. Just do it and see.As someone else said its easier to go faster in a group.

Good Luck

 

[vickster]

If you like pooting, try CTC or Skyrides...where are you in Surrey?

Cateye among others make some cost effective little computers just to monitor speed and distance, you don't need a garmin

e.g. wired http://www.chainreactioncycles.com/cateye-velo-5-function/rp-prod26194

 

[moo]

The simple cheap units will often be more accurate at lower speeds than the GPS Garmin, especially if you stop/start a lot.

 

[fairyhedgehog]

Any group ride specifically aimed at newcomers to groups should ensure no one gets left behind really.

That's reassuring. I would like not to hold them up too much, though!

 

[fairyhedgehog]

I have two bikes with the basic Halfords wireless cycle computer and both have worked well over a lot of miles. They are about £20.

Definitely go for a wireless one .They look much neater on the bike.

Re cycling with the club , most clubs/groups will let you ride a few times before joining to see if its for you. Just do it and see.As someone else said its easier to go faster in a group.

Good Luck

Thanks for the recommendations for wireless computers. £20 sounds like a reasonable price to pay!

 

[fairyhedgehog]

If you like pooting, try CTC or Skyrides...where are you in Surrey?

Cateye among others make some cost effective little computers just to monitor speed and distance, you don't need a garmin

e.g. wired http://www.chainreactioncycles.com/cateye-velo-5-function/rp-prod26194

I'm in Epsom and I've checked out those websites you mentioned and they look helpful. Some of the rides might be in my range!

And thanks for the Cateye recommendation.

 

[fairyhedgehog]

The simple cheap units will often be more accurate at lower speeds than the GPS Garmin, especially if you stop/start a lot.

That's good to know!

And round here there is a lot of stopping and starting for traffic lights because I'm mostly staying on the roads. I don't cycle much in the parks in the winter because it's too boggy. I had a nasty jolt the other day in Nonsuch Park when I cycled through a puddle and it had a pothole in the middle!

 

[ColinJ]

You can calculate your speed for nothing if you know what your gear ratio and your cadence (revs/min of your pedal action) are!

Count your pedal revs in one minute - that is your cadence. Call that 'Cad'.

Count the number of teeth on the chainring (front 'cog') that you are using. Call that 'Front'.

Count the number of teeth on the sprocket (rear 'cog') that you are using. Call that 'Rear'.

Get somebody to hold you upright on your bike with a clear straight run of at least 8 feet ahead of you. Line the valve on the front wheel up with the ground. Mark that position on the road. Roll forwards slowly until the valve is back in that position again. Mark the road again. Measure the distance between the 2 points in mm. That is the circumference of your tyre. Call that 'Circ'. (It is more accurate to measure the circumference that way than just wheeling your bike forward yourself because your weight will compress your tyres slightly and reduce their effective circumference.)

Your speed in km/hour is (60 * Cad * Circ * Front) / (1,000 * 1,000 * Rear) ~= (Cad * Circ * Front) / (16,667 * Rear)

The '60' converts rev/min to rev/hour. The first '1,000' converts mm to metres, the second, metres to kms.

If you prefer miles/hr then introduce a conversion factor of 1.609, so speed in miles/hr = (60 * Cad * Circ * Front) / (1,000 * 1,000 * 1.609 * Rear) or ~= (Cad * Circ * Front) / (26817 * Rear).

This is not quite as complicated as it sounds. Alternatively, if you think it IS - buy a computer or GPS, or use your smartphone!

 

[fairyhedgehog]

You can calculate your speed for nothing if you know what your gear ratio and your cadence

[...]

If you prefer miles/hr then introduce a conversion factor of 1.609, so speed in miles/hr = (60 * Cad * Circ * Front) / (1,000 * 1,000 * 1.609 * Rear) or ~= (Cad * Circ * Front) / (26817 * Rear).

This is not quite as complicated as it sounds. Alternatively, if you think it IS - buy a computer or GPS, or use your smartphone!

I can see how that would work. On the other hand, a wireless bike computer is being to sound like an easier option!