<div dir="ltr"><div dir="ltr"><div>Mike,</div><div><br></div><div>Thanks and appreciate the additional feedback. I have a R888s on another set of wheels, but have not driven with them yet. I would be interested in the results of your head to head comparison. I think the R888s are harder tires from what I understand, but similar temp ranges. </div><div><br></div><div>After more research, I have decided to stick with the Hoosier TDRs. Just feels the right thing to do even with the technical differences.</div><div><br></div><div>For those that might be interested, the Hoosier R8s will require a front camber of (2.0) to (3.5) and a rear camber of about (2.0), which would be difficult to achieve with the TR6, without radically changing the front suspension. I would rather stay vintage than make those kind of changes. While at it, curiosity lead me to compare the Speedster to the TDR. I found the Speedster, being a radial, also requires a higher camber as well. Otherwise, with a camber of less than (2.0), it would wear the outside of the tire more, and grip would be less.</div><div><br></div><div>Most of the FOT may already be aware of these differences, but some of this is still new to me. I learned that the HOTD-R tires use the same compound as the Hoosier R7s (the Hoosier chart below confirms this). The Speedster uses a different compound, but has similar temperature ranges and hardness (S9).</div><div><br></div><div>Thanks again for the response and hope the below helps those that might be interested in looking at different tires.</div><div><br></div><div>Regards,</div><div><br></div><div>Mark Cook</div><div><br></div><div><br></div><div><br></div><div>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><b><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></b></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><b><span style="font-size:12pt;font-family:"Arial","sans-serif"">Hoosier
Speedster Overview<span></span></span></b></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">The
Speedster is a modern DOT-approved racing radial disguised with a
period-correct vintage tread pattern.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Setup Requirements: Because it is a radial, it demands significantly more
negative camber <b>(often -2.5 to -3.5 degrees total) </b>to keep the tread
flat under heavy cornering loads. It also relies on lower cold inflation
pressures compared to bias tires to achieve its optimal hot footprint.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Performance Profile: It yields high absolute peak cornering speeds and sharp
steering response. However, the limit of adhesion can be more abrupt than a
traditional bias tire.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><b><span style="font-size:12pt;font-family:"Arial","sans-serif"">Hoosier
HOTD-R Overview<span></span></span></b></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">The
HOTD-R (Historic Old Timer Design - Radial/Race designation variant) represents
Hoosier's flagship bias-ply evolution for strict vintage rules.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Setup Requirements: It functions exceptionally well on traditional vintage
suspension setups with modest negative camber <b>(e.g., -1.5 degrees).</b> It
uses stiffer sidewalls that preserve fender clearance under load without requiring
heavy static lean angles.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Performance Profile: The HOTD-R allows drivers to lean aggressively on the
tire, sliding the car predictably through corners. It handles heat cycles
gracefully and functions at a broader slip angle, matching the classic driving
style expected in historic motorsport classes.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><b><span style="font-size:12pt;font-family:"Arial","sans-serif"">Hoosier
Speedster Camber Profile<span></span></span></b></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Target Front Camber: -2.5° to -3.5° of negative camber is required.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Target Rear Camber: -1.5° to -2.0° of negative camber.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Mechanical Necessity: As a radial tire, the sidewall is designed to flex
dynamically under lateral load. Without aggressive negative camber, the tire
will roll onto its outer shoulder, causing rapid outer tread wear, a severe
drop-off in grip, and potential center-rib blistering. Achieving these specs on
vintage suspension often requires modified upper control arms, slotted pivots,
or offset bushings.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><b><span style="font-size:12pt;font-family:"Arial","sans-serif"">Hoosier
HOTD-R Camber Profile<span></span></span></b></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Target Front Camber: -1.0° to -1.5° of negative camber is ideal.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Target Rear Camber: -0.5° to -1.0° of negative camber.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Mechanical Necessity: The HOTD-R utilizes a stiff bias-ply construction. The
tire carcass is structurally rigid and resists rolling under cornering force,
meaning the tread stays flat relative to the wheel. If you run excessive
negative camber (over -2.0°) on a HOTD-R, you will ride strictly on the inner
edge of the tire in a straight line, overheating the inner carcass and reducing
braking efficiency.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">The
differences in carcass construction between the Hoosier Speedster and the
Hoosier HOTD-R dictate two entirely distinct driving styles on track. Driving a
radial requires high precision and managing a sharp edge, while driving a
bias-ply style tire requires managing weight transfer and driving with the
throttle through a slide.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">1.
Slip Angle Management<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Hoosier Speedster: Requires low slip angles. You must keep the car tracking
cleanly along the optimal geometric line. The tire delivers its peak grip with
very little slip (typically 4 to 7 degrees). If you over-drive the tire and
force the car into a slide, the grip drops off abruptly, causing the car to
snap or scrub off significant corner speed.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Hoosier HOTD-R: Thrives on high slip angles. This tire is designed for
traditional vintage four-wheel drifts. Peak adhesion occurs at a much wider
slip angle (8 to 12+ degrees). The breakaway characteristic is incredibly
progressive, allowing you to deliberately slide the rear end to help rotate the
car without losing momentum or risking a sudden spin.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">2.
Steering Inputs & Precision<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Hoosier Speedster: Demands smooth, minimal, and precise inputs. Because the
modern radial construction provides a sharp, immediate steering response,
aggressive hand movements will overload the front contact patch. You must feed
the steering in gently and catch slides instantly before they exceed the tire's
narrow peak grip window.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Hoosier HOTD-R: Requires proactive, deliberate, and busier steering. The stiff
carcass design responds beautifully to aggressive initial turn-in to set the
platform. Once the car is balanced in the corner, you will find yourself
constantly modulating the steering wheel and balancing the car's attitude using
fine adjustments of the throttle.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">3.
Braking and Corner Transitions<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Hoosier Speedster: Favors straight-line threshold braking. Radials maximize
their longitudinal grip when flat. You want to get the heavy braking done while
the wheels are pointed straight, then transition smoothly off the brake pedal
as you initiate turn-in (trail braking must be managed carefully to avoid
overloading the front outer tire shoulder).<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif"">•
Hoosier HOTD-R: Excels at aggressive trail braking and pitch management.
Because the tire carcass remains stable under compression, you can carry the
brakes deep into the apex to pin the nose and break the rear traction loose
intentionally. The tire is highly forgiving during rapid weight transitions,
allowing you to manipulate the car's balance mid-corner using the chassis'
natural roll.<span></span></span></p>
<p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><span style="font-size:12pt;font-family:"Arial","sans-serif""><span> </span></span></p><br><br><br><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:11pt;font-family:"Calibri","sans-serif""><br></p>
<br></div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Thu, Oct 8, 2026 at 9:36 AM Mike Harmuth <<a href="mailto:ofracer@gmail.com">ofracer@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hi Mark. I've been using the Hoosier TDRs for years on my Spit and all groups accept them. This year, I had, what turned out to be a mounting problem, with a fresh set of TDRs and I needed tires ASAP after the K Cup so I bought a set of Toyo Proxies R888R (full width tread tires). Again, these are allowed with every racing group. They have a smaller diameter than the TDRs which helped me in the boot at the Glen but not so much on the straights. I've sorted out the mounting problems with the TDRs so I plan on a back to back comparison next weekend at Thompson to see what works best there (slower track, probably the Toyos).<div><br></div><div>Our racing group, HRG, allows the R7s and similar tires at every event except our joint weekend at the Glen with VRG. That's the one VRG event (out of 3 last year) where HRG tire rules were not allowed.</div><div><br></div><div>mike h</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Oct 6, 2026 at 12:34 PM Mark Cook <<a href="mailto:mecook635@gmail.com" target="_blank">mecook635@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr"><div>Just following up on my earlier email to see if anyone has thought about the tire rules and my question below.</div><div><br></div><div>Thanks,</div><div><br></div><div>Mark Cook</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Oct 4, 2026 at 8:21 AM Mark Cook <<a href="mailto:mecook635@gmail.com" target="_blank">mecook635@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>All,</div><div><br></div><div>So, I it is time to replace my Hoosier TDRs on my TR6. This TR6 was previously run in SCCA with Hoosier R7 SM7.5 (Spec Miata). When I purchased the TR6 In 2024, then current VDCA/SVRA tire rules did not allow these tires and I switched to the TDRs.</div><div><br></div><div>In 2026 SVRA and VDCA changed the rules for Group 8/CP to allow the Hoosier R7/R8, as well as the Toyo Proxes RR. It appears that VRG and VSCCA continue to require fully treaded tires in CP/DP classes, like the Hoosier Speedster and TDR. Though, VRG is deferring to other organizations tire rules in joint events (VIR / Summit Point with VDCA as example).</div><div><br></div><div>I think most of you run in VDCA Group 3, but has anyone running in Group 8 CP/DP changed or considering changing to Hoosier R8s or Toyo Proxes RR? </div><div><br></div><div>Thanks,</div><div><br></div><div>Mark Cook</div><div><br></div></div>
</blockquote></div></div>
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