Transfixed06

hello guys, yes yet ANOTHER pista question. did a pretty extensive search in the pic threads, as well as velospace to no avail. just wondering what the lugged S. Rush fork would look like on a Pista. anyone?

shants

i'm sure that your imagination -- or a bit of photoshop ghettoriggery -- will do the trick.

that said, i've seen lugged forks on pistas before, but they were threaded. i think they look a lot better than stok unicrown.

dijos

why a rush fork, specifically?
THere are a few logged Cr-mo Chrome forks available cheaper, also.

TedC

Other than the spicer, what is out there?

freeskihp

bikeworks NYC generic chrome fork, $40

dijos

thank you, I couldn't find it.

TedC

how much clearance is there on those forks?

Cynikal 

FYI - the bikeworks fork has a rake around 45mm the stock pista is 28mm (I think?). The BW fork is great, I have one but it's a road bike fork not a track fork.

MIN 

It's not to much of a mental jump to picture this on your frame, is it?

Cynikal 

I run 25's without issue.

Nakedjim

Where can you get 28mm rake carbon areo forks? I have been trying to find them without luck.

DoshKel

Jamtastic's bike (with BikeworksNYC's fork):



Burritos' bike (with Soma Rush, Mercier Kilo TT, KHS Flite 100 fork):

Transfixed06

i've been offered a brand new Tange Prestige fork off of a soma frame for around the same price as the bikeworks. plus its threadless like the stock pista fork, and the BW fork isnt) just wanted to see if a pic existed of the TP fork actually on a pista to get a better idea of the difference in rake. thanks for the input, people.

Batson

Heres a pic of a pista with a soma fork.

BuddyMike

the some fork is 1inch unthreaded. So make sure the pista is 1inch.

Transfixed06

thanks batson!

buddy- it is indeed 1 inch threadless.

bryyando

wouldnt the handling of the bike change pretty significantly? sorry for the necro but thinking of the same thing. but if it doesnt really change it, does it reduce toe overlap?

Ken Cox

The Bianchi Pista frame has a 75 degree head tube angle; the steepest angle of any factory bike ever made.

The Bianchi Pista fork has 28mm of rake; the shortest rake of any factory bike ever made.

The steep head tube angle and the short rake go together for a reason.

Anvil Bikes provides a "trail calculator" on their site.

https://www.anvilbikes.com/images/1064634020.xls

The above requires Excel to run, however, if one plays with this program it will make the significance of the steep head tube angle and the short rake very clear.

In comparison, Mercian's purpose-built track frameset, the Super Vigorelli, has a head tube angle of 74 degrees and a rake of 33mm.

In a good handling bike, as the head tube angle relaxes, the rake increases; and vice versa.

I think the Bianchi Pista as it comes from the factory has the best combination of quick steering and stability possible.

Don't put a steep head tube angle and a long rake together unless you need some additional excitement in your life.

bryyando

the pista in my size would only have a 71.5 angle. and according the charts the highest it goes up to is 73. where do you find info for the fork?

Ken Cox

I visited the Bianchi USA site and, looking at the 2009 Pista, I can see where bryyando got his/her figures.

However, these numbers represent such a divergence from Bianchi's past figures for this bike's geometry (even the largest frame size has a head tube angle of only 73 degrees) that I suspect a typographical error or a misplaced graphic.

I have tried to look at the geometry of previous years (which include rake) on the Bianchi site and I get error messages.

In any event, I consider a 71.5 head tube angle for a track bike, or even a road bike, unbelievably slack.

Try playing with Anvil Bike's trail calculator:

https://www.anvilbikes.com/images/1064634020.xls

A head tube angle of 71.5 degrees and a rake of 28mm would give a trail of 69.6mm; a dimension right at the edge of unacceptably slow handling, and perhaps more suitable for an expedition bike intended to go 10,000 miles with a rider and six months of camping gear.

For comparison, Mercian's Super Vigorelli, with a head tube angle of 74 degrees and a rake of 33mm, has a trail of 61.4mm, about right in the middle of acceptable handling.

Quite possibly, Bianchi has in fact changed the geometry of the Pista in order to make it as boringly tame a bike as possible for newby fixed gear riders.

I find this hard to believe.

Well, I checked a little further, and I looked at the Surly Steamroller's geometry, just for more comparison.

The Steamroller, in its smallest frame size, has a head tube angle of 72.5 degrees and a rake of 38mm, which comes out as a very relaxed trail of 65.5mm.

The largest Steamroller frame has a head tube angle of 74 degrees, which, with a rake of 38mm, gives a trail of 56.2mm, or fairly quick.

All of this has me wondering if perhaps the wheelbase plays more of a factor in the handling than I realize.

If a significantly shorter wheelbase would also significantly quicken the handling of a bike, then this would explain why Surly and, apparently, Bianchi have relaxed the head tube angle in smaller sized frames.

Hm.

Fascinating.

adriano 

i have a 47cm kilo. this conversation makes me wonder what the real specifications are. i know the steering is average if not slow.

chase.

smaller frame sizes often have relaxed angles to reduce toe overlap and increase frame clearance, just as larger sizes have a tighter front end to keep the wheelbase reasonably short.

ianjk

lolz.

adriano 

yes, and since the 47 isnt a khs, definite numbers arent easily found.

chase.

mercier/BD have never published solid information about their frame geometry for the kilo, unfortunately. i