Cam MTB - the Cambridge Mountain Bikers' Forum

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  • Wear a helmet. Despite recent advances in medical science, brains still cannot be mended nor replaced.
  • Wear gloves or mitts. Hands often hit the ground first. Cuts and grazes invite infection and a hospital visit.
  • Wear eye protection, it only takes a twig or thorn to lose an eye. Crud catchers are a good idea in mucky weather.
  • When downhilling, for your own protection, allow plenty of space behind the rider in front.
  • Bring a bare minimum emergency tool kit and a spare inner tube.
  • Breakdowns are a bore. Plan not to have any by ensuring your bike is in perfect working order.
  • Punctures are also tedious. You can minimise them by fitting latex tubes, slime tubes or running tubeless tyres.

Photo: CAMMTB Winter 2022-23 rides have been posted up - please click on the Runs List link..

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Choosing a new bike

Hi, Hoping people on here can help me. I am looking to get back into mountain biking , I have been out once before with you guys probably around 18 months ago. Had a 26" wheel hardtail.

I am now looking to get a new bike but can't decide what would be best for the type of routes you all ride. I am thinking a 29er hardtail with 100-120mm suspension fork? Do i need rear suspension at all?

Re: Choosing a new bike

I'll try...

Rigid single speeds are still the height of fashion.

If like me you aren't fit enough for one gear, 29 hardtails are great.

Some people do come out on full bouncers, which are probably not necessary for the weeknight rides, but if you're looking to ride elsewhere and only have the (money/space/spousal tolerance) for one then a trail bike would not be out of place.

There are plenty of people still on 26ers. They seem to keep up/be at the front, but don't let me stop you getting a new bike

Re: Choosing a new bike

Not intending to derail this thread, but hats off for introducing me to the term 'Spousal tolerance'.

@Andy (assuming the correct one) - as a structural engineer please can you present the inclusion of spousal tolerance within the formula "optimum number of bikes = n+1" at some point in the future?

Re: Choosing a new bike

B = n + 1 < d

B = number of bikes optimum
n = current number of bikes
d = divorce threshold

Re: Choosing a new bike

This is good but I think we may be over simplifying it and actually there are specific formulae for both single and settled cyclists. For single, B= n+1 is fine. However, once settled I think B is perhaps not so much a function of the number of bikes currently owned (n). But is actually driven by the relationship between spousal tolerance (s) and divorce/breakup threshold (d). In summary, I think that if settled, B is found in the inter-dimensional space between (s) and (d) - the 'sweet spot' if you will.

My logical lingo may be incorrect but how about:

Single: B = n+1
Settled: B = s < x < d

In the settled scenario (s) is defined as p≥n where (p) is perceived likelihood of divorce/breakup on a scale of (1 to n+1) where (n) is, as usual, the number of bikes currently owned.


1. I currently own 2 bikes, I want to buy a 3rd, and as my other half is nice so (p) is low at 1 on a scale of 1 to 3 (2+1). the p:n is 1:3. It is therefore okay to buy - but I am not yet at the optimum B

2. I currently own 9 bikes, my other half is not nice so (p) is 10 on a scale of 1 to 10 (9+1). the p:n is 10:9 - buying another bike would therefore exceed the spousal tolerance and propel you into the target zone B (remember B = s < x < d). It is therefore okay to buy.

There must be an online tool for this somewhere - if not we should build one and add it to the site.

Re: Choosing a new bike

Please come out with us Ian, We aren't all like this

Re: Choosing a new bike

Maybe not all but i sense a lot are!

Given there are some seemingly intelligent people in this group (thinking Paul L and his multivariate analysis based award)we should try and figure this out properly and arrive at a universal rule such as 'half your age plus 7'

Re: Choosing a new bike

Would it be possible to employ your services (possibly with a useful gpx to % discount rate) to work out my own personal bikes to spouse tolerance calculation as I am running out of space and still do not seem to be anywhere near the amount required for the required reaction

Re: Choosing a new bike

Going back to the bike question, 29ers are great around here, try to get one with sliding drop outs. Try to buy second hand where it's common to find a one or two year old £2-3000 bike selling or can, with persuasion be bought for £800-£1000.
This is what I like to do, it gets you onto a fantastic bike for very little money. Mate of mine from Leeds just bought a two year old 5.5" travel yeti rolling frame with 150 Fox forks and hope/stans wheels for £800.00. Jon Mynott recently bought a pristine £1500.00 do it all 2yr old bike for £550.00 which buying new at this price point would not get you a particularly good steed.
Need any help, give me a bell.... There's bargains in these here Hills!

Re: Choosing a new bike

Adrian, you overthought this I think! The B = n + 1 < d formula is pretty well established and is codified in Rule #12 (, although most of the rules are for roadies this one goes for all cyclists).

Re: Choosing a new bike

Adrian & co:
Does your formula cover what happens when you go from state of affairs = Single to state of affairs = Settled?

E.g. is it possible that n may immediately cause spousal intolerance and therefore n must be immediately reduced (clearly undesirable)?

OR is is possible that if you get n high enough before changing the state of affairs, the new spouse is thus "trained" to enable a low p-rate when trying to make the transition from n to n+1 in the newly settled state (thus meaning while single buy as many bikes as possible, meaning when meeting new spouse, they think of this as normal)

How is spousal intolerance rate p calculated and what factors affect it? E.g possibly it can be increased by obtaining a house with a large garage?

Re: Choosing a new bike

As with the application of any formula it is possible to apply external factors which may be difficult to quantify and therefore to prove but which are nonetheless influential.

In my own case (small garage and no motivation to move or space to enlarge) I apply the M factor.

The M factor is dependent on keeping the current garage in a condition akin to the Magiceye pictures where one has to focus through the apparent clutter and disorder to be able to truly see what lies beyond. In my experience this deters unwelcome spousal investigation into the contents of said garage

Re: Choosing a new bike

These are good questions/suggestions.

@clare - I admit that as these formulae are still in formation, accounting for a change in relationship status has not yet been considered. This is an interesting area though so leave it with me.

As for your second question, do you need clarity on 'Spousal tolerance' (s) or 'Perceived likelihood of breakup/divorce' (p)? You seem to be confusing the two.

@Tony - great input. I think (M) could be neatly applied to to the basic concept on N+1(M). So N+1 could actually be N+2 or 3 depending on your ability to strongly express the M factor. However, is the M factor robust, could spousal eyesight (E), or garage light bulb performance (L) not influence the expression of M?

Rather than rehashing an existing formula. Perhaps over beers after a ride we can sketch out all the parameters and rebuild from scratch.

Re: Choosing a new bike

Adrian, I've just realised that your bike helmet is in the garage somewhere. Sorry.

Re: Choosing a new bike

I quite like the 'Chippy Chris' formula which circumvents the spousal tolerance factors:-

B = n + 2N

B = the optimum number of bikes
n = n is the number of bikes that you currently have
N = the number of sheds that you have in your back garden that you tell your wife are associated with your self-employed trade that you can secrete at least two bikes in, preferably those that look identical to your current bikes.

Ian - I go with advice above. I am a committed FS trail bike rider, owning 2 nice 26'er bikes which are great fun in most conditions, especially summer when the trails are firmer. However, I bought a second-hand 29'er fully rigid rolling-chassis from Duncan which I have now built up into a nice, light winter bike.

Pasty Tom