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PostPosted: Wed Sep 04, 2013 2:33 pm 
retrobike rider / Gold Trader
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Joined: Sat May 09, 2009 11:46 pm
Posts: 4023
Location: East Riding of Yorkshire
shogun wrote:
I doubt it because the traction needs of a singlespeed are barely any different than a geared bike and surely you'd want less weight on the wheel you are spinning with your legs?

They're very different if the gearing forces you up out of the saddle on climbs in my experience.

PostPosted: Thu Sep 05, 2013 1:49 am 
Retro Guru

Joined: Sat Dec 29, 2007 7:21 am
Posts: 881
Location: Hobart, Tasmania, Australia
I have my doubts that running a wide rear tyre would make any significant difference to that. Given the profile of most off-road tyres the difference between say 1.9 and 2.1 in tread contacting the ground while climbing would be a couple of mm literally. Different story when you look at volume and shock absorbing properties favouring running a wider front.

PostPosted: Thu Sep 05, 2013 7:25 am 
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Joined: Tue Aug 07, 2007 12:22 pm
Posts: 2947
Location: Platsa, Messinias, Greece
bishopdante wrote:
it's actually slightly narrower than the contact patch on the front, 1.2, which has a flatter circular profile and a good 180mm of travel in the forks.

You use a hardtail with 180mm of fork travel on the road ? :shock:.
Why, and what on earth is it ??

PostPosted: Thu Sep 05, 2013 10:02 am 
retrobike rider / Gold Trader
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Joined: Fri May 08, 2009 10:01 am
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Location: Stockport, staring at the Peaks
Was just wondering that too!

Back in the late nineties when all my friends were buying - or in one case, home-building! - sus forks with as much as 2" of travel*, I'd blown my student loan on the Ibis Alibi frame so had to stick with the tb P2s dug out of the back of the lbs (still on there). So I bought a Maxxis Mofo dh 2.35 for the front which gave me about as much travel as them!

Worked a treat with a fast IRC V-Claw on the back (wanted!), and still does to this day.

On a 100mm hardtail I'll run a matched pair though.

*one crazy downhiller even had three inches. Three!!! Crazy.

PostPosted: Sat Sep 07, 2013 9:01 pm 
retrobike rider
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Joined: Fri Aug 08, 2008 2:36 pm
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Location: Yorkshire, England
Quite oddly I used to run a narrow IRC GeoClaw Lite on the front at a good proper retro pressure, it would grip nicely and the Mag21's would take the hits out.
The wider 1.9/1.95 on the rear for me would do the propelling (usually a Psycho if not being a weenie Smoke Lite)

Light weight, grip and everything I needed.

I didn't do the large front tyre thing.

Though since this is brought up as a Retro Way of doing things (which didn't happen around this part of the world/my extended group BiTD) I've just fitted a 2.1 Splashback tot he front and 1.8 Splashback to the rear for the Peaks ride. both fekking huge tyres compared to the Smoke Lite I first did it on.)
It'll be like that unless the weather turns and I need something grippier.

PostPosted: Tue Sep 17, 2013 3:22 am 
Dirt Disciple

Joined: Mon Sep 02, 2013 12:22 am
Posts: 50
Location: London
Andy R wrote:
bishopdante wrote:
it's actually slightly narrower than the contact patch on the front, 1.2, which has a flatter circular profile and a good 180mm of travel in the forks.

You use a hardtail with 180mm of fork travel on the road ? :shock:.
Why, and what on earth is it ??

It's a no-name ally hardtail, built like a tank, with a bunch of retroreflective tape stuck to it. The tubing might even be solid for all I know, it's heavy like that, was welded as part of a batch for a local shop here. The frame is probably going away soon, to be replaced with a bamboo hardtail frame, all the rest of the bits are perfect for the job. Forks are dual crown Marzocchi bombers.

Been riding it with roughly this frankenstein part DH part cycle courier setup for 4 years, and I haven't yet met (fingers crossed) a traffic situation it wasn't happy to intervene in and remain composed, which couldn't be said for its many predecessors, lots of which were various sorts of skinny tyre racers and road bikes.

Racers are nice and fast, good for distance, but I would not, in my experience, advise riding one in London in traffic.

Distinctly remember one situation on a racer where a small flatbed truck mini-lorry was driving like a maniac downhill on a backstreet, 8.40am, blasted right past me at 50mph straddling both lanes. I was coasting along, skirting the parked cars all down the left with 1ft gaps between, he overtook me at the bottom of the road, ignored the give way marks at the left turn only T junction onto a busy main road, got slightly out into the junction, no grip downhill at speed, and was surprised by a passing vehicle which had unexpectedly pulled out of the flow of traffic to cross his path, pulling out into the seemingly empty lane at speed on the busy 4 lane main road junction, equally surprised to be meeting a mean looking trash-truck swinging out of a tiny backstreet head-on at speed. The flatbed's emergency stop caused him to skid and then reverse at speed lurching backwards, a sort of half baked three point turn causing his vehicle to block the whole T junction, I'd originally given him 20 feet clearance at 20mph heading round the right of him... seen him indicate turning left, so headed to the right outside his turning circle, blocking my view of the junction and the undertaking head-on vehicle, I met some unpleasant lumpy end-of road patch feature, glanced down to investigate, 20 feet turned over half a second into nothing... looked up and the truck leaving the junction lurched around suddenly, the bed cantilevered out over the back axle, swinging 10 feet out to cut off my path, had to swerve left to go the other way around where there was now some space and probably a nice big kerb to kick the front wheel in, back brake just didn't have enough bite to even slow me down to anything sensible, steering didn't have any bite, just understeer wobble, so better stop doing that, then the truck snapped back at me a few feet on its suspension as I met it and the bed punched me right in the handlebars, the front wheel buckled before my eyes straight into the rear quarter blind spot a few feet behind the wheel arch, I ended up flipped over the bars into the flatbed truck rolling around on on a pile of scrap and old fridges, the truck's silhouette was bashed into the front wheel like a cartoon with the bike wrapped up & around the truck, took us 10 minutes to get the bike off his truck, the metal of the bike had formed itself around his chassis. Not even the back wheel escaped writeoff.

On the current bike just a reflex dab of both brakes and some fork compression would have brought me to a near standstill more than a car's length before the junction, even in the wet, then hop up onto the pavement and just roll round the junction blocking traffic incident at walking pace. A rigid fork will produce horrid skittering understeer on patchy tarmac, especially in rainy conditions.

On racers I've ended up in people's cars (suddenly opened door), over the tops of cars, holding onto the sides of buses, stuck like spiderman onto the sides of black cabs, into car boots. It can turn from just normal traffic, getting where you're going, into "hey... oh you utter ***... BAM" and you've entered a new reality where you're no longer riding a bicycle, the bike logged out a few seconds back, because some custodian of a piece of heavy machinery decided to do something innovative and hasty on the road and fill a space which was occupied a second after they saw it. Vehicle drivers are really impatient in crowded streets, they lash out like cornered animals when territorial disputes occur, and they don't look where they're headed half the time. Guy I know currently has a broken arm from a car door opening move. That was riding a Brompton with road-greased dirty brake blocks.

The conditions here in London are harsh and unforgiving for cyclists. Never know what you might run into, or where you might need to divert your course to, often don't get a lot of time to find out & respond accordingly.

Every few weeks in the local paper there's some story of some student who bought a bike to save money, and got pulled under a lorry, which ate the back wheel first followed by everything else. Even with two lanes between you and it, with a crosswind you can feel the suction as one passes at speed.

Often you have to head off the road onto whatever else presents itself, and London has a variety of street furniture. Bottoming out a fork on a concrete or granite surface will do plenty damage to your forks, so if one has travel, one needs enough of it to never bottom out. Either no suspension or plenty of travel, or it'll die quite fast, loads of dead shock problems from road riding in London in bike shops, really common.

Good forks keep the front wheel on the ground at all times, which is where it should be if you plan on steering. In a bad situation (eg worn tarmac surface going patchy peeling back near the kerb to victorian cobble stones, in the wet with a bunch of motor oil on top, while getting boxed in front & back at 25mph coming down kensal rise in heavy traffic, then run into the kerb and then emergency stop cut-up by an SUV mounting the kerb driven by a russian gangster who is arguing on his phone and looking the other way and almost crashed into oncoming traffic with his super-wide tinted out jeep [few weeks back's scary moment]) – so long as the front wheel is going along properly, the rear wheel can get proper ugly out of shape under heavy braking on a very uneven slippery/catchy rock hard surface, and it all snaps back in line quickly and helpfully rather than vomiting you onto the pavement or under the wheels of a vehicle, giving you enough time and composure to make an escape.

If you lose the front, as can happen on a racer, you are now a passenger headed on a train in roughly one direction.

This mountain bike has so far in 4 years not been in any crashes, I've been able to ride out of the various traffic ambushes so far (fingers crossed), although usually some traffic situation gives you a good fright every few weeks.

TBH the various surfaces under Con Dem Nation are getting into an appalling condition, all sorts of sunken fissures, lumps, drains, manholes, sleeping policemen, seams, potholes and sagged road works patches, so I'm building a full suspension bike so that I can ride sitting down all the time not 1/3 of the time.


So I'd guess that'd the thinking behind the big front tire is simply that you can't afford to sacrifice grip on the front.

In the case of off road knobbly tires, the rolling resistance is quite expensive for the amount of grip, so it's arguable that the best way to go is to sacrifice some grip on the back where it's less critical for braking and steering.

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