Search found 305 matches

by rareposter
27 Jul 2021, 2:49pm
Forum: Does anyone know … ?
Topic: Newbie needing a little advice on tire/tube sizes.
Replies: 5
Views: 57

Re: Newbie needing a little advice on tire/tube sizes.

PeteLittle1970 wrote: 27 Jul 2021, 2:11pm
42 - 622 [28 x 1.60 - 700x400)3.5-6.0 bar 50-85 psi
42 is the width in mm. General rule is that wider tyres are more comfy, can be run at lower pressures and give more grip especially on uneven terrain but they're usually slower than narrower tyres.
Most road (racer type) bike will be about 25-28mm, hybrids and CX bikes about 32-38 and e-bikes (plus a lot of the more extreme gravel bikes) will be around 42-48. Normally the tyre width is dependent on the rim width - if you have a really narrow rim, you can't fit really wide tyres.

622 is the rim size which (confusingly) is 700c. Vast majority of road, CX/gravel and hybrid / touring style bikes are 700c although as mentioned earlier, the rim width will vary - road bikes will have narrower rims than gravel bikes.

3.5 - 6.0 is the pressure in bar
50 - 85 is the pressure in psi
for that combination of tyre & rim. Narrower tyres, you'll need to run higher pressures, wider tyres you can run lower.

Next thing - what is causing the punctures? Is it a spoke poking through the rim bed or is it something cutting through the tyre? Usually, unless the tyre is very worn, a lot of punctures indicates something in the wheel rather than an issue with the tyre. Give it all a very careful check. Schwalbe Marathons are durable and tough but also known for weighing a lot and having a rather harsh ride quality...
by rareposter
20 Jul 2021, 10:17pm
Forum: Bikes & Bits – Technical section
Topic: 40T Cassette On A Road Bike
Replies: 45
Views: 1171

Re: 40T Cassette On A Road Bike

biketips666 wrote: 20 Jul 2021, 5:31pm
50/34 with 11-34 is a range of 454%

my 48/38/26 with 11-34 is a range of 572%

I wouldn't call those "similar".

I've had an even greater range, when the inner was a 24, which worked fine.
Sure, you get a wider range but at the expense of a large number of gears in the middle which are virtually identical
38-15 is the same as 48-19
48-27 is almost identical to 38-21
There's loads of crossover.

The whole point of a double is that you just use a wider range cassette - so where you'd use a triple with an 11-34, with a double you'd use an 11-42 or 11-46. Same range, less weight, more usable gears without the crossover, plus shifting on the rear is much easier than the front, especially under load so it's more efficient.
by rareposter
20 Jul 2021, 3:37pm
Forum: Bikes & Bits – Technical section
Topic: 40T Cassette On A Road Bike
Replies: 45
Views: 1171

Re: 40T Cassette On A Road Bike

Mick F wrote: 19 Jul 2021, 5:16pm Why are triples out of fashion?
It's less about ratios and more about how much a front mech *really* limits frame design - less so on road bikes but certainly on gravel and MTB, Having a front mech there is a hugely limiting factor in frame design (especially Q-factor), tyre clearance, mud clearance and suspension pivot placement.

Rear mechs can now handle far greater range than previous designs so for most applications of "normal" usage, it's perfectly sensible to dispense with the front mech and shifting arrangement. It also frees up space on the bars to accommodate the control for a dropper post. On a related note, most beginners find it easier to only have one set of gears to think about.

The one downside is that to drop quickly from a high gear into a low gear requires a sweep up 8-9 cogs at the back vs a single shift at the front to go from big ring to small ring but as a general rule that's not a major issue.
by rareposter
19 Jul 2021, 8:51am
Forum: Lands End to John O'Groats
Topic: Training for lejog
Replies: 22
Views: 885

Re: Lejog training enquiry :)

I agree with everything that @Paulatic said in the first reply.

Riding on a turbo is great for doing specific workouts, intervals, sprints etc which can be difficult to do in the real world where terrain and traffic can interfere with sticking to a certain power or HR.

However, you absolutely need real world riding to learn about traffic, group riding, bike handling, "reading the road", navigation (and use of whatever nav kit you're using), clothing, how to pack and carry your stuff, eating and drinking on the move, pacing, bike fit and so on.

I've done a lot of ride leading (including on LEJOG events) and invariably there'll be someone there who is reasonably fit and strong from doing a load of virtual riding, Zwift etc but has zero clue about group riding, what to wear for the weather, how to ride in inclement conditions (that could be wind/rain or, like now, a heatwave).

You say you live in quite a busy area - are there options where you could get a train out of town and then ride back? At least that way you can get most of the ride done on quieter roads.
by rareposter
14 Jul 2021, 1:05pm
Forum: Does anyone know … ?
Topic: Optimum Cycling Position
Replies: 76
Views: 2626

Re: Optimum Cycling Position

rogerzilla wrote: 14 Jul 2021, 7:38am Bike fits are snake oil, in my opinion. People are too different in flexibility and riding style.
I dunno, in the right circumstances they can be quite useful. Many people completely new to cycling have no idea of what should be where or what the "ideal" position is for that type of bike and as a result end up in all sorts of weird positions. It might be "right" in as much as they're not suffering any injury but equally, in terms of efficiency, comfort, weight distribution and handling, it'll be totally off. The problem is that new people don't really know this so they just end up "making do" or unconsciously compensating. So in that respect, a decent fit can help and it'll show how things need to change as they get fitter, stronger and so on.

But yeah, with the sheer number of bike types out there, the changes in fashion, standards and geometry over the years, and (worst of all) the massive expansion of "advice" on the internet via YouTube, forums etc, it's become a minefield. Technically it should be one bike fit per bike and even that will only give a starting point to adjust from; you could realistically re-fit yourself every year and adjust based on fitness, goals, weight/flexibility (gain or loss) and so on.

Where it becomes snake oil is not necessarily the actual bike fit but the person doing it - there are plenty of people out there who have been trained on how to use System X who then describe themselves as professional bike fitters.
by rareposter
14 Jul 2021, 10:32am
Forum: Does anyone know … ?
Topic: Tour de France on TV
Replies: 40
Views: 1524

Re: Tour de France on TV

Darkman wrote: 14 Jul 2021, 10:13am It's not so much the length of ads that bugs me, more the content.

The majority fall into three categories on Sky:
1. Past-their-sellby-date celebrities trying to flog life insurance and/or dodgy-looking medical aids that probably don't work.
2. Old people having a jolly good pissup because one of them's just paid for his own funeral.
3. For just £2 a month, you can adopt a tiger, a snow leopard, a panda, a donkey, an elephant, a polar bear, an African orphan boy...
Yeah, you could accrue quite the menagerie with all of those adverts for animal rescue!
I always thought it was a pity that the donkey and the poor African girl that has to walk 10 miles for water couldn't just be paired up. ;-)

Still, it's better than those Watchfinder adverts from a couple of years ago when the whole ITV4 coverage was sponsored by them and it had a guy (badly) riding a bike with the focus on his expensive watch.
by rareposter
13 Jul 2021, 9:54am
Forum: Bikes & Bits – Technical section
Topic: Bike computer and tyre circumference
Replies: 45
Views: 1099

Re: Bike computer and tyre circumference

As @MickF said - there's no maths involved, no reading of tyre values (most values are not anything close to what the manufacturer suggests for many reasons - rim width, pressure, ideas of how tyres are measured...).

Run a steel tape measure out along a smooth flat level hard surface to about 2.5m. Inflate tyres to the pressure you intend to ride them at then roll the front wheel along the measure for 1 full revolution - you can measure using the valve or just put a dot of tippex/permanent marker/chalk on the tyre wall. Repeat a few times then take an average.

If you want to be super precise you should be riding the bike so the tyre can deform as your weight is on it but frankly the logistics of that and the actual difference it makes is not worth it.

Take that value in mm and input it into the computer. Job done, the computer does the rest of counting revolutions, adding up the distance travelled each time and converting to miles or km.

Once out in the real world you can compare the readings against known distances or against a GPS - they're unlikely to match precisely but they'll be to within a few fractions of a %.
by rareposter
12 Jul 2021, 4:36pm
Forum: On the road
Topic: What the fudge!!!????
Replies: 5
Views: 417

Re: What the fudge!!!????

On an incredibly pedantic note, you can't have attempted manslaughter.

Manslaughter is when the victim dies but it was not intended - ie you only intended to use force on them.
Murder is obviously going out with the intent to kill someone and succeeding in that.
Attempted murder is the above but failing.

You can't really prove attempted murder on that - while it's fairly obvious that throwing an axe at someone is likely to do them serious harm, it'd be very difficult proving the intention to murder.

Given that there is no suspect, no witness and no actual injury caused, the chances of any investigation
(a) being done in the first place and
(b) succeeding
are incredibly small. You could dust the axe for prints and then search through CCTV for any white van at that time and (assuming of course that such footage still exists) if you find vans matching that rather generic description of a white high-top, you can question and fingerprint the driver but that's unlikely to lead anywhere either since it will have been a passenger who'll have thrown anything; the driver can deny all knowledge very easily.
I can see why they've said no investigation - it's very unlikely to actually lead anywhere.
by rareposter
11 Jul 2021, 6:07pm
Forum: Bikes & Bits – Technical section
Topic: Bike designs which should be binned
Replies: 353
Views: 13161

Re: Bike designs which should be binned

jb wrote: 9 Jul 2021, 1:00pm I've ridden stoney tracks with my fingers on the rear shock and it doesn't seem to react in time with bumps. It's fine on bigger stuff as my back can testify (which is the reason I went full suspension) but small bumps - I remain to be convinced.
If you're reaching back to hold the rear shock while riding then I'm guessing you're not going full gas! Also, your weight will be weirdly distributed.

Easier to see it working while riding alongside - or maybe get someone to video you in slow motion as you ride past and you'll be able to see the shock working. Unless it's set up wrong... ;-)
by rareposter
10 Jul 2021, 10:25pm
Forum: Bikes & Bits – Technical section
Topic: Bike designs which should be binned
Replies: 353
Views: 13161

Re: Bike designs which should be binned

Mick F wrote: 10 Jul 2021, 12:37pm What was wrong with the Kirk?
Heavy (due to the amount of material needed and the way it was built as two halves welded/glued together) and incredibly flexy. Also very prone to breaking - magnesium is quite brittle.

They did an MTB version too, a mate had one. Well actually, he had several, they all snapped and were replaced under warranty. If you sprinted out of the saddle, there was so much flex in the back end that it would spontaneously change gear.

They looked cool and obviously the technology to work with that material was in its infancy but the whole idea was terrible!
by rareposter
9 Jul 2021, 4:32pm
Forum: Bikes & Bits – Technical section
Topic: Bike designs which should be binned
Replies: 353
Views: 13161

Re: Bike designs which should be binned

Stevek76 wrote: 9 Jul 2021, 12:03pm Lefty forks have generally been limited to XC racing where weight is considered important and travel can be short.

Surprised no one's commented on the rear part of that gravel bike, looks like they're using the flex of the carbon frame as the rear suspension.
That's been done plenty of times.
Ibis did a bike called the Bow Ti which was a full sus frame with 5" of rear wheel travel driven entirely by flex in the titanium frame, no pivots at all.

On road, loads of companies use carbon sometimes with integrated rubber dampers to deliberately induce flex in the desired direction to improve comfort.
by rareposter
9 Jul 2021, 11:47am
Forum: Bikes & Bits – Technical section
Topic: Bike designs which should be binned
Replies: 353
Views: 13161

Re: Bike designs which should be binned

mig wrote: 9 Jul 2021, 10:21am not read the whole thread but i seem to remember "power cranks" in the 90s? some sort of pedal one side through a revolution then repeat on t'other whilst 'foot 1' remains still. something like that !!
You mean this pile of junk?
https://www.powercranks.com/

On a related note, does anyone remember the L-shaped cranks thing - a thankfully very short-lived phase of drivetrain development.

Image
by rareposter
9 Jul 2021, 9:17am
Forum: Bikes & Bits – Technical section
Topic: Bike designs which should be binned
Replies: 353
Views: 13161

Re: Bike designs which should be binned

roger wrote: 8 Jul 2021, 10:22pm Was'n't it a Mike Burrows initiative?
It was - the Lotus track bike was single-sided on both sides:

Image
by rareposter
8 Jul 2021, 10:19pm
Forum: Bikes & Bits – Technical section
Topic: Bike designs which should be binned
Replies: 353
Views: 13161

Re: Bike designs which should be binned

Lefty forks have been around for decades - it's primarily a Cannondale thing but USE had a single-leg fork on the market for many years too.

Advantages are mud clearance (acres of it!), the fact you don't need to remove the wheel to change a tyre and it's lighter weight than regular forks. It's also very stiff - the internal cross section is square or hexagonal so there's zero flex or twist in it.

Also, that basic design of a strut with a wheel on one side is how vehicle wheels work. Even aircraft wheels are that sort of design. There's nothing wrong with it, it's not some kind of new never-tried-before thing.

Disadvantages - obviously you need a specific front hub and they only work with disc brakes.
Also, you have to put up with every other person telling you that part of your bike is missing. Much the same as tandem pilots hear the same "joke" about the person on the back not pedalling.
Yes, it's hilarious the first time but you're the 23rd person today who's said that...
by rareposter
8 Jul 2021, 5:46pm
Forum: Bikes & Bits – Technical section
Topic: Bike designs which should be binned
Replies: 353
Views: 13161

Re: Bike designs which should be binned

iandusud wrote: 8 Jul 2021, 4:52pm
The Deceuninck-Quick Step team are using clinchers with inner tubes at the TDF this year with some success! Other teams are using tubeless clinchers and others tubular.
The latest wheelset on those S-Works is a Specialized in-house brand called Roval (they're very good) and those latest wheels are specifically clincher only - not tubeless. Something to do with the manufacturing process and I suspect how quickly they needed to be on the market. All the other Roval wheels in the range are tubeless ready, it's just that top-end set that is clincher only.

As usual, as with all new kit, they're lighter, faster, stronger and make the rider more attractive... ;-)