Here is a great video from the Oregon Manifest event in October. Info about our entry, The Donna, can be found here.
We're teaming up with Paragon Machine Works to produce a very limited run of titanium WiseCracker LITE bottle openers for the holidays. These will be sized to fit any 1-1/8" steer tube and will come with a lightly polished finish.
Price will be set at $35 per unit including domestic shipping. Send an email to 'mike at ahrensbicycles dot com' to pre-order yours today!
Posted by Mike Ahrens at 9:01 AM
Great day yesterday at the SF Bike Expo at the Cow Palace and special thanks to my sister Elizabeth for helping out. Our booth was right across from the indoor dirt track used for the 'cross races. We brought three bikes to the event....a white monster 'cross frame, red 650b hardtail and gray urban 'cross bike. Customer turnout was good and we will surely do it again next year!
Posted by Mike Ahrens at 9:29 PM
Here are some more in process photos of Kristy's single speed hardtail. The head tube rings are machined on the front side of the tube only....this leaves more material on the back side of the tube for strength. Machining rings into head tubes is common across the industry...but machining eccentric (off-center) rings is more difficult and is rarely seen on production frames.
Small vent holes inside the frame allow the inside tube surfaces to be purged with nitrogen; this gas runs through the red flexible tubing which is attached to the welding fixture. This means no impurities will be present after welding which is important since inspecting inside the frame is nearly impossible with conventional tools. Prior to welding, all key joint surfaces are thoroughly cleaned and deburred.
The Easton Ultralite 'pear shaped' down tube is bi-ovalized for strength and maximum weld area at the head tube and BB shell. This tube is so tall it accounts for more than half the real estate of the head tube! As a result, the top tube receives an interference cut to 'cup' the down tube and head tube for the ideal mating fit. The top tube is also bi-ovalized to maximize joint strength at either end.
The rear triangle components are pre-assembled ahead of time in a special fixture designed by Anvil and then integrated into the main Anvil fixture to create a complete frame. The rear dropouts are spaced slightly wide at 137mm to account for slight spring-back which can happen when welding bike frames. In this case, the spring back is minimal due to the shape and rigidity of the upper/lower yoke components.
During fabrication, the sliding dropouts are positioned all the way forward which translates into a 16.5" chainstay length (measured center-to-center). Once the bike is assembled, the sliders will be re-positioned between 16.5-17.2" depending on the desired riding characteristics. I usually set this distance to ~16.8" to strike a balance between climbing and descending ability. Too short and the bike will be unruly during high-speed descents. Too long and climbing response is reduced. Since the dropouts can slide, it's very easy for the end user to dial in their ideal chainstay length on their home turf.
When working with aluminum, material availability can become an issue since it's imported in very small quantities to the USA. As a result, I've started to develop frames using round rear stays (in lieu of rectangular tubes) that are hand-formed for the ideal fit before welding. In this case, the chainstays are 25mm round and then swaged near the dropout joint. The seatstays are 22mm diameter tubes with similar treatment as the chainstays. The ride quality of the round tubes is excellent and on par with the classic rectangular stays used up to this point.
I expect this frame to weigh in under 3.6 lbs which should provide an excellent platform for single speeding!
Posted by Mike Ahrens at 12:28 PM
Here are some pics of a belt drive dropout conversion created by frame builder Chris Kopp. The dropouts are split in the seatstay zone and then attached back together with a simple backing plate. Looking forward to seeing the completed frame...
Posted by Mike Ahrens at 10:34 PM
I have quite a few frames in the queue right now and I'm excited that business has been picking up this quarter. This year has been slower than normal due to the economy and it's nice to attract some new customers!
Since my wife's bike was recently stolen, we decided to replace it with a step-thru, single speed townie frame. This frame will be outfitted with a Shimano Alfine drivetrain, dual disc brakes and fat 26" city tires. We also plan to install a front basket for quick trips around the neighborhood.
Next up is another single speed mountain frame for Kristy in the mid-west. This is a smaller frame that will be setup with a Fox F32 80mm travel fork, King wheelset and Race Face components...here are pics of the pre-cut tubes before welding the entire frame together.
More pics to follow as these projects (and others) near completion. And if you're in the Bay Area, be sure to stop by our booth at the SF BIKE EXPO next weekend! We'll be selling some old inventory and of course the ever popular WiseCracker bottle opener just in time for the holidaze.
Posted by Mike Ahrens at 9:38 AM
I just finished assembling my new commute bike and I can't wait to log some saddle time on this baby. As shown it weighs in at just over 22 lbs with dual disc brakes and mostly MTB drivetrain including XTR shifters and rear derailleur, XT 12-32 cassette and dual-pull front derailleur, and Shimano R600 compact cranks with Race Face 36/46 chain rings.
The front end geometry is setup around a Wound Up CX disc fork and tallish head tube for a more upright body position. The bars are the FSA Metropolis model; basically a modern mustache bar with 31.8mm center diameter. They are flipped over to hit my hands in just the right spot.
Frame geometry is derived from the standard Whole Shot 'cross lineup which has been evolving over the past few years.
The left side/ISO disc dropout is triangulated with a support tube welded between the seatstays and chainstays. Sliding dropouts are used for extra flexibility in case I want to convert this bike to one speed. The front/rear brakes are Hope Mono Minis with Scrub metal matrix rotors.
Special thanks to Paragon for supplying the brass 'jam nuts' used on the sliding dropouts...way better than the standard ones I've been using.
Kenda Kommando cross tires mated to Velocity VXC rims (painted to match the frame) and Sun Flea disc hubs round out the whole package.
Posted by Mike Ahrens at 5:33 PM
Last year I sent a frame to East Coast racer James and he recently broke the rear derailleur hanger due to muddy course conditions. It's an easy fix with dropouts from Paragon Machine Works...the hanger will be replaced with a stiffer 7075 aluminum version. Over email I told James about our new Euro-style cable routing and some subtle changes to the lower yoke. As a racer, his feedback is very valuable to me as a designer...see below:
The frame changes sound cool. I noticed the Euro style frame on the blog this summer. Very nice frame. My older bikes [steel IF Planet X's] all have top tube routing. In all honesty, I dont think there is much difference between top tube vs. downtube routing. I've found that the collection points for mud are the brakes and front derailleur itself. The yoke dosen't catch any more stuff than other designs. I think the yoke design gives more clearance betwwen the crank arms, chainrings and stays towards the BB junction. I race in both the New England and the Mid-Atlantic areas. Mostly dry to damp conditions overall. When we do get mud it mixes with grass and makes things clog up quickly. That's what happened when I snapped my hanger. In retrospect, I should have swapped bikes midway through the race. Again, thanks.
Here's another useful thread on 'cross cable routing from the Mud & Cowbells site:
Which type of routing is better? Everything on the top tube? Ultimately it's the rider's choice and Ahrens Bicycles is happy to deliver your preference.
Posted by Mike Ahrens at 8:16 PM
Last week I signed up for the SF Bike Expo at the Cow Palace - check out the press release. Last time I was at the Cow Palace was for a Metallica concert - funny. Looking forward to displaying a new Monster Cross frame and our usual assortment of road and mountain bikes. Plenty of WiseCrackers will be on hand just in time for the holidays.
Posted by Mike Ahrens at 3:14 PM
Two weeks after the event, many builders are talking about their experiences at the Oregon Manifest event....great feedback can be found here. I definitely agree that the design criteria, race and final judging were not well aligned. After investing a fair amount of resources on this project, I'm a little frustrated by the results (or lack thereof) for Ahrens Bicycles. Some award winning bikes clearly had construction issues which is pretty surprising given the 'constructor's challenge' event theme.
On the flip side, the purpose of events like these is to garner exposure while providing participants a chance to learn some new things. I saw innovative design solutions all over the place and this by itself is inspiring for my own future projects in the commuter/utility space. My bike was the only entry made from aluminum which shows how slanted events like this are towards steel frames. My main takeaway is that The Donna is a versatile bike that works well for my customer and meets her needs nicely.....and hopefully this success leads to more frame sales to keep the business moving.
Posted by Mike Ahrens at 2:52 PM
Last weekend we traveled to Portland, OR for the Oregon Manifest Constructor's Design Challenge. This event involved designing, building and racing a commuter bike in and around Portland. My friend Donna raced her bike, aptly named The Donna, nearly 77 miles over varied terrain including road, gravel and dirt. Below is a picture from the start....Donna was one of only two women racing. I am very proud of her for tackling this event only one week after her wedding! Big props to newlyweds Donna and Lee from Ahrens Bicycles! The second woman to race was Natalie from Sweet Pea Bicycles racing on a custom Ahearne commuter bike.
The first starting group was Donna, Natalie and a guy racing on the nearly 60-lb Metrofiets cargo bike. After about 25 miles, the real hard part began with a challenging gravel fire road climb that was relentless. Not too many photos are available because during Donna's climb, Steve Rex, another racer/frame builder was injured with a broken collar bone and I took him to the hospital! Luckily Steve is OK and recovering back home in Sactown.
The Rapha beer stop was at mile 38. Donna's husband Lee and I enjoyed a couple of beers at this check point...this is where I found out Steve Rex had injured his collar bone. Curtis Ingliss from Retrotec called the Rapha race coordinator from a farm and relayed the message.
Here's our crew at the finish including college friends Chris and Henry and of course Donna and myself. Not sure where Lee is hiding...probably scoring us some more beer.
There were many aspects of turning The Donna into a true commuter bike from its origin as a single speed . I prototyped a rear rack with some cardboard and a fabric bag from Andronico's market. This exercise helped me determine the rack proportions before actual fabrication began.
Four solid aluminum struts support the rear rack and these are hard-mounted to the frame. Adjustable eyelets were sourced from Bontrager to allow height adjustment and final leveling of the rack. One special feature of this bike is the integrated lock. A custom seat clamp was developed to include a Thule lock core and a coil lock. Turn the key and the lock releases the cable which can then be used to lock the bike. I'm really proud of this feature because it's truly unique and someone even asked me "where did you buy that lock?" at the event.
The front rack is cantilever-mounted to the head tube using WiseCracker extruded aluminum mounts. The upper mount is a tall headset spacer and the lower mount cups the fork crown and is installed with a star nut on the underside. Wooden slats were stained black and mounted to both racks to achieve a classic look.
Special thanks to Princeton Tec for supplying the lighting solutions for this project. Light and bright, these babies are sick.
All these extra features added some weight to the overall bike but it was still manageable to ride. Special thanks to everyone that made this bike and event possible...there are way too many to list here.
Posted by Mike Ahrens at 8:22 PM
The mint green 29er was recently raced at the Single Speed World Championships in Durango. Here is a great race report from Anthony:
Sliding dropouts keep the rear disc brake aligned to the rotor and tension the chain at the same time. The dropout hoods can accommodate a variety of frame sizes and geometries.
Tire clearance at the upper yoke is ample even when running large air volume tires.
Same goes for the lower yoke.
The bike's stance is oriented towards aggressive XC riding with a slightly slackened head angle and adjustable wheelbase.
Posted by Mike Ahrens at 9:34 AM
================ALUMINUM REVOLVER 29er================
First off is a sea foam green Revolver 29er for Anthony in New Mexico. This is a replacement frame for a single speed 29er prototype that I built for myself and then sold to Anthony earlier this year. The first frame was just too light and the rear triangle is tweaked....I won't know what went wrong until I have a chance to measure the original but my instinct tells me the tubing was not beefy enough to handle single speed 29er loads. So back to the drawing board to design and deliver Anthony a new frame in time for the Single Speed World Championships this month in Durango. Fully built pics just added below!
I went back to my roots with Anthony's new 29er and dug up some stout rectangular bmx-style chainstays that were used throughout the rear triangle. I've been saving these specific tubes for a project just like this and the rear triangle on this bike is STIFF. The upper and lower yokes are machined from 25mm thick 7005 bar stock with an emphasis on lateral rigidity, not lightweight. The rear sliding dropouts have also been beefed up for 2009 and I finally sourced a fully-threaded M5 tensioning bolt! I've been looking for this type of bolt for a long time and finally someone offered some affordable custom ones for me! Rounding off the rear triangle is a the wishbone tube....no-nonsense 1" square material with straight wall thickness.
Huge ass tire clearance was a request easily met with the machined yokes. Also notice the slit in the seat tube faces forward to keep water and dirt out of the Chris King bottom bracket.
The front triangle uses Easton Ultralite material including a 32mm seat tube, 38mm top tube and 44.5mm down tube which is extra long for the 29er application. The front-end geometry of this frame is a little slacker than what most builders are using but for the high-speed descents that Anthony rides, a little wheel flop while climbing steep stuff is an acceptable tradeoff. More images to follow one this new Revolver is built up.
================STEEL REVOLVER 29er================
The second 29er project is for local rider Will. It's important to note that Will is an experienced brewmaster...that's right, he makes beer for a living. Needless to say I was more than happy to get this project rolling! After a few conversations at the start of the project, Will settled on a steel 29er with a build kit anyone would love. Fox F29 fork with 80mm of travel and new FIT cartridge. Full XTR. New XT 29er wheelset. King, Thomson, Race Face, Crank Bros and WTB round off the rest of the parts.
The steel tubeset was sourced through Nova Cycle Supply and it features s-bend rear triangle tubing for ample tire clearance. Rear dropouts are Paragon hoods with a replaceable hanger - not so common on steel bikes! Geometry is sized just right for Will based on fit measurements he provided at the start of the project.
I'm looking forward to Will's first ride report which will be coming soon....
Posted by Mike Ahrens at 9:59 PM